UL
®
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
f
CKO
f
CKi
Vss
SS/
SCK
MISO
MOSI
LS7366
(631) 271-0400 FAX (631) 271-0405
A3800
32-BIT QUADRATURE COUNTER WITH SERIAL INTERFACE
GENERAL FEATURES:
• Operating voltage: 3.0V to 5.5V (V
DD
- V
SS
)
• 5V count frequency: 40MHz
• 3V count frequency: 20MHz
• 32-bit counter (CNTR).
• 32-bit data register (DTR) and comparator.
• 32-bit output register (OTR).
• Two 8-bit mode registers (MDR0, MDR1) for programmable
functional modes.
• 8-bit instruction register (IR).
• 8-bit status register (STR).
• Latched Interrupt output on Carry or Borrow or Compare or Index.
• Index driven counter load, output register load or counter reset.
• Internal quadrature clock decoder and filter.
• x1, x2 or x4 mode of quadrature counting.
• Non-quadrature up/down counting.
• Modulo-N, Non-recycle, Range-limit or
Free-running modes of counting
• 8-bit, 16-bit, 24-bit and 32-bit programmable configuration
synchronous (SPI) serial interface
• LS7366 (DIP); LS7366-S (SOIC); LS7366-TS (TSSOP)
- See Figure 1-
SPI/MICROWIRE
(Serial Peripheral Interface):
• Standard 4-wire connection: MOSI, MISO, SS/ and SCK.
• Slave mode only.
GENERAL DESCRIPTION:
LS7366 is a 32-bit CMOS counter, with direct interface for quadra-
ture clocks from incremental encoders. It also interfaces with the
index signals from incremental encoders to perform variety of
marker functions.
For communications with microprocessors or microcontrollers, it
provides a 4-wire SPI/MICROWIRE bus.The four standard bus I/Os
are SS/, SCK, MISO and MOSI. The data transfer between a micro-
controller and a slave LS7366 is synchronous. The synchronization
is done by the SCK clocks supplied by the microcontroller.
Each transmission is organized in blocks of 1 to 5 bytes of data.
A transmission cycle is intitiated by a high to low transition of the
SS/ input. The first byte received in a transmission cycle is always
an instruction byte, whereas the second through the fifth bytes are
always interpreted as data bytes. A transmission cycle is terminated
with the low to high transition of the SS/ input. Received bytes are
shifted in at the MOSI input, MSB first, with the leading edges
(high transition) of the SCK clocks. Output data are shifted out on
the MISO output, MSB first, with the trailing edges (low transition)
of the SCK clocks.
7366-111805-1
November 2005
PIN ASSIGNMENT
TOP VIEW
14
13
12
LS7366
11
10
9
8
FIGURE 1
V
DD
CNT_EN
A
B
INDEX
DFLAG/
LFLAG/
1
2
3
4
5
6
7
Read and write commands cannot be combined.
For example, when the device is shifting out read
data on MISO output, it ignores the MOSI input,
even though the SS/ input is active. SS/ must be
terminated and reasserted before the device will
accept a new command.
The counter can be configured to operate as a
1, 2, 3 or 4-byte counter. When configured as a
n-byte counter, the CNTR, DTR and OTR are all
configured as n-byte registers, where n = 1, 2, 3 or
4. The content of the instruction/data identity is
automatically adjusted to match the n-byte configu-
ration. For example, if the counter is configured as a
2-byte counter, the instruction “write to DTR”
expects 2 data bytes following the instruction byte.
If the counter is configured as a 3-byte counter, the
same instruction will expect 3 bytes of data follow-
ing the instruction byte.
Following the transfer of the appropriate number of
bytes any further attempt of data transfer is ignored
until a new instruction cycle is started by switching
the SS/ input to high and then low.
The counter can be programmed to operate in a
number of different modes, with the operating
characteristics being written into the two mode
registers MDR0 and MDR1. Hardware I/Os are
provided for event driven operations, such as
processor interrupt and index related functions.
I/O Pins:
Following is a description of all the input/output pins.
A (Pin
12)
B
(Pin 11)
Inputs. A and B quadrature clock outputs from incremental
encoders are directly applied to the A and B inputs of the
LS7366. These clocks are ideally 90 degrees out-of-phase
signals. A and B inputs are validated by on-chip digital filters
and then decoded for up/down direction and count clocks.
In non-quadrature mode, A serves as the count input and
B serves as the direction input (B = high enables up count,
B = low enables down count). In non-quadrature mode,
the A and B inputs are not filtered internally, and are
instantaneous in nature.
INDEX
(Pin 10)
Input. The INDEX is a programmable input that can
be driven directly by the Index output of an incremental
encoder. It can be programmed via the MDR to function
as one of the following:
LCNTR (load CNTR with data from DTR), RCNTR
(reset CNTR), or LOTR (load OTR with data from CNTR).
Alternatively, the INDEX input can be masked out for
"no functionality".
In quadrature mode, the INDEX input is validated with the
filter clock in order to synchronize with the quadrature inputs
A and B. To be valid, the INDEX signal in quadrature mode
must overlap the condition in which both A and B are low or
both A and B are high. In non-quadrature mode, however,
the INDEX input is instantaneous in nature and totally
independent of A and B.
f
CKi
(Pin 2),
f
CK0
(Pin 1)
Input, Output. A crystal connected between these 2 pins
generates the basic clock for filtering the A, B and INDEX
inputs in the quadrature count mode. Instead of a crystal the
f
CKi
input may also be driven by an external clock.
The frequency at the f
CKi
input is either divided by 2
(if MDR0 <B7> = 1) or divided by 1 (if MDR0 <B7> = 0)
for the filter circuit. For proper filtering of the A, B and
the Index inputs the following condition must be satisfied:
LFLAG/
(Pin 8),
DFLAG/
(Pin 9)
Outputs. LFLAG/ and DFLAG/ are programmable outputs to flag
the occurences of Carry (counter overflow), Borrow (counter
underflow), Compare (CNTR = DTR) and INDEX. The LFLAG/ is
an open drain latched output. In contrast, the DFLAG/ is a push-
pull instantaneous output. The LFLAG/ can be wired in multi-
slave configuration, forming a single processor interrupt line.
When active LFLAG/ switches to logic 0 and can be restored to
the high impedence state only by clearing the status register,
STR. In contrast, the DFLAG/ dynamically switches low with
occurences of Carry, Borrow, Compare and INDEX conditions.
The configuration of LFLAG/ and DFLAG/ are made through the
control register MDR1. In free-running count mode LFLAG/ and
DFLAG/ output the same status information in latched and
dynamic form, respectively. In single-cycle mode the DFLAG/
outputs CY and BW signals independent of the MDR1 configura-
tion. In range-limit and modulo-n modes, DFLAG/ outputs CMP
signal in count-up direction (at CNTR = DTR) and BW signal
when CNTR underflows independent of the MDR1 configuration.
In effect, DFLAG/ generates mode-relevant marker signals in all
modes, excepting the free-running count mode wherein MDR1
configures the output signal selection.
MOSI (RXD)
(Pin 7)
Input. Serial output data from the host processor is shifted into
the LS7366 at this input.
MISO (TXD)
(Pin 6)
Output. Serial output data from the LS7366 is shifted out on the
MISO (Master In Slave Out) pin. The MISO output goes into
high impedance state when SS/ input is at logic high, providing
multiple slave-unit serial outputs to be wire-ORed.
SCK
(Pin 5)
Input. The SCK input serves as the shift clock input for transmit-
ting data in and out of LS7366 on the MOSI and the MISO pins,
respectively. Since the LS7366 can operate only in the slave
mode, the SCK signal is provided by the host processor as a
means for synchronizing the serial transmission between itself
and the slave LS7366.
REGISTERS:
The following is a list of LS7366 internal registers:
Upon power-up the registers DTR, CNTR, STR, MDR0 and
MDR1 are reset to zero.
DTR.
The DTR is a software configurable 8, 16, 24 or 32-bit
input data register which can be written into directly from MOSI,
the serial input. The DTR data can be transferred into the 32-bit
counter (CNTR) under program control or by hardware index
signal. The DTR can be cleared to zero by software control.
In certain count modes, such as modulo-n and range-limit,
DTR holds the data for "n" and the count range, respectively.
In compare operations, whereby compare flag is set, the DTR is
compared with the CNTR.
f
f
≥
4f
QA
Where f
f
is the internal filter clock frequency derived from the
fCKi in accordance with the status of MDR0 <B7> and f
QA
is
the maximum frequency of Clock A in quadrature mode.
In non-quadrature count mode, f
CKi
is not used and should
be tied off to any stable logic state.
SS/
(Pin 4)
A high to low transition at the SS/ (Slave Select) input
selects the LS7366 for serial bi-directional data transfer;
a low to high transition disables serial data transfer
and brings the MISO output to high impedance state.
This allows for the accommodation of multiple slave units
on the serial I/O.
CNT_EN
(Pin 12)
Input. Counting is enabled when CNT_EN input is high;
counting is disabled when this input is low.
There is an internal pull-up resistor on this input.
7366-012405-2
CNTR.
The CNTR is a software configurable 8, 16, 24 or 32-bit up/down counter which counts the up/down pulses resulting from
the quadrature clocks applied at the A and B inputs, or alternatively, in non-quadrature mode, pulses applied at the A input. By
means of IR intructions the CNTR can be cleared, loaded from the DTR or in turn, can be transferred into the OTR. The “clear CNTR”
and the “load CNTR” commands in the ”range-limit” mode, however have limitations. In this mode when the CNTR is frozen in up count
direction at CNTR = DTR, a “clear CNTR” command will only function if the count direction is reversed from up to down. Similarly,
in the down direction at CNTR = 0, a “load CNTR” command will only function if the direction is reversed from down to up.
OTR.
The OTR is a software configuration 8, 16, 24 or 32-bit register which can be read back on the MISO output.
Since instantaneous CNTR value is often needed to be read while the CNTR continues to count, the OTR serves as a
convenient dump site for instantaneous CNTR data which can then be read without interfering with the counting process.
STR.
The STR is an 8-bit status register which stores
count related status information.
CY
7
BW
6
CMP
5
IDX
4
CEN
3
PLS
2
U/D
1
S
0
PLS: Power loss indicator latch; set upon power up
U/D: Count direction indicator: 0: count down, 1: count up
S: Sign bit. 1: negative, 0: positive
A “CLR STR” command to IR resets all status bits except CEN
and U/D. In quadrature mode, if the quadrature clocks have
been halted, the status bits CY, BW and CMP are not affected
by a “CLR STR” command under the following conditions:
CY: If CNTR = FFFFFFFF with status bit U/D = 1
BW: If CNTR = 0 with status bit U/D = 0
CMP: If CNTR = DTR
In non-quadrature mode the same rules apply if input A is held at
logic low.
B2 B1 B0 = XXX (Don’t care)
B5 B4 B3 = 000: Select none
= 001: Select MDR0
= 010: Select MDR1
= 011: Select DTR
= 100: Select CNTR
= 101: Select OTR
= 110: Select STR
= 111: Select none
B7 B6 = 00: CLR register
= 01: RD register
= 10: WR register
= 11: LOAD register
CY: Carry (CNTR overflow) latch
BW: Borrow (CNTR underflow) latch
CMP: Compare (CNTR = DTR) latch
IDX: Index latch
CEN: Count enable status: 0: counting disabled,
1: counting enabled
IR.
The IR is an 8-bit register that fetches instruction bytes from
the received data stream and executes them to perform such
functions as setting up the operating mode for the chip (load the
MDR) and data transfer among the various registers.
B7
B6
B5
B4
B3
B2
B1
B0
The actions of the four functions, CLR, RD, WR and LOAD are elaborated in Table 1.
TABLE 1
Register
MDR0
MRD1
DTR
CNTR
OTR
STR
MDR0
MDR1
DTR
CNTR
OTR
STR
MDR0
MDR1
DTR
CNTR
OTR
STR
MDR0
MDR1
DTR
CNTR
OTR
Number of Bytes OP Code
1
CLR
2 to 5
RD
2 to 5
WR
1
LOAD
Operation
Clear MDR0 to zero
Clear MDR1 to zero
None
Clear CNTR to zero
None
Clear STR to zero
Output MDR0 serially on TXD (MISO)
Output MDR1 serially on TXD (MISO)
None
Transfer CNTR to OTR, then output OTR serially
on TXD (MISO)
Output OTR serially on TXD (MISO)
Output STR serially on TXD (MISO)
Write serial data at RXD (MOSI) into MDR0
Write serial data at RXD (MOSI) into MDR1
Write serial data at RXD (MOSI) into DTR
None
None
None
None
None
None
Transfer DTR to CNTR in “parallel”
Transfer CNTR to OTR in “parallel”
7366-0823005-3
MDR0.
The MDR0 (Mode Register 0) is an 8-bit read/write register that sets up the operating mode for the LS7366. The MDR0 is
written into by executing the "write-to-MDR0" instruction via the instruction register. Upon power up MDR0 is cleared to zero.
The following is a breakdown of the MDR bits:
B7
B6
B5
B4
B3
B2
B1
B0
B1 B0 = 00: non-quadrature count mode. (A = clock, B = direction).
= 01: x1 quadrature count mode (one count per quadrature cycle).
= 10: x2 quadrature count mode (two counts per quadrature cycle).
= 11: x4 quadrature count mode (four counts per quadrature cycle).
B3 B2 = 00: free-running count mode.
= 01: single-cycle count mode (counter disabled with carry or borrow, re-enabled with reset or load).
= 10: range-limit count mode (up and down count-ranges are limited between DTR and zero,
respectively; counting freezes at these limits but resumes when direction reverses).
= 11: modulo-n count mode (input count clock frequency is divided by a factor of (n+1),
where n = DTR, in both up and down directions).
B5 B4 = 00: disable index.
= 01: configure index as the "load CNTR" input (transfers DTR to CNTR).
= 10: configure index as the "reset CNTR" input (clears CNTR to 0).
= 11: configure index as the "load OTR" input (transfers CNTR to OTR).
B6 = 0:
= 1:
B7 = 0:
= 1:
Negative index input
Positive index input
Filter clock division factor = 1
Filter clock division factor = 2
MDR1.
The MDR1 (Mode Register 1) is an 8-bit read/write register which is appended to MDR0 for additional modes.
Upon power-up MDR1 is cleared to zero.
B7
B1 B0 = 00:
= 01:
= 10:
= 11:
B2 = 0:
= 1:
B3 = :
B4 = 0:
= 1:
B5 = 0:
= 1:
B6 = 0:
= 1:
B7 = 0:
= 1:
B6
B5
B4
B3
B2
B1
B0
4-byte counter mode
3-byte counter mode
2-byte counter mode.
1-byte counter mode
Enable counting
Disable counting
not used
NOP
FLAG on IDX (B4 of STR)
NOP
FLAG on CMP (B5 of STR)
NOP
FLAG on BW (B6 of STR)
NOP
FLAG on CY (B7 of STR)
NOTE:
Applicable to both
LFLAG/ and DFLAG/
ABSOLUTE MAXIMUM RATINGS:
(All voltages referenced to Vss)
Parameter
DC Supply Voltage
Voltage
Operating Temperature
Storage Temperature
Symbol
V
DD
V
IN
T
A
T
STG
Values
+7.0
Vss - 0.3 to V
DD
+ 0.3
-25 to +85
-65 to +150
Unit
V
V
oC
oC
7366-112204-4
DC Electrical Characteristics.
(T
A
= -25˚C to +85°C)
Parameter
Supply Voltage
Supply Current
Input Voltages:
f
CKi
, Logic High
f
CKi
, Logic Low
All other inputs, Logic High
Symbol
V
DD
I
DD
I
DD
V
CH
V
CH
V
CL
V
CL
V
AH
V
AH
V
AL
V
AL
I
IEL
I
IEL
I
IEH
I
IEH
-
I
OFL
I
OFL
-0
I
OCL
I
OCL
I
OCH
I
OCH
I
OML
I
OML
I
OMH
I
OMH
Min.
3.0
300
700
2.3
3.7
-
-
2.1
3.5
-
-
-
-
-
-
-
-1.3
-3.2
0
-1.3
-3.2
1.3
3.2
-1.5
-3.8
1.5
3.8
TYP
-
400
800
-
-
-
-
-
-
-
-
3.0
10.0
1.0
4.0
0
-2.0
-4.0
-
-2.0
-4.0
2.0
4.0
-2.4
-4.8
2.4
4.8
Max.
5.5
450
950
-
-
0.7
1.3
-
-
0.5
1.0
5.0
15.0
3.0
6.0
0
-
-
-
-
-
-
-
-
-
-
-
Unit
V
µA
µA
V
V
V
V
V
V
V
V
µA
µA
µA
µA
µA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
Remarks
-
V
DD
= 3.0V
V
DD
= 5.0V
V
DD
= 3.0V
V
DD
= 5.0V
V
DD
= 3.0V
V
DD
= 5.0V
V
DD
= 3.0V
V
DD
= 5.0V
V
DD
= 3.0V
V
DD
= 5.0V
V
AL
= 0.7V, V
DD
= 3.0V
V
AL
= 1.2V, V
DD
= 5.0V
V
AH
= 1.9V, V
DD
= 3.0V
V
AH
= 3.2V, V
DD
= 5.0V
-
V
OUT
= 0.5V, V
DD
= 3.0V
V
OUT
= 0.5V, V
DD
= 5.0V
Open Drain Output
V
OUT
V
OUT
V
OUT
V
OUT
= 0.5V, V
DD
= 3.0V
= 0.5V, V
DD
= 5.0V
= 2.5V, V
DD
= 3.0V
= 4.5V, V
DD
= 5.0V
All other inputs, Logic Low
Input Currents:
CNT_EN Low
CNT_EN High
All other inputs, High or Low
Output Currents:
FLAG Sink
FLAG Source
f
CKO
Sink
f
CKO
Source
TXD/MISO:
Sink
V
OUT
= 0.5V, V
DD
= 3.0V
V
OUT
= 0.5V, V
DD
= 5.0V
V
OUT
= 0.5V, V
DD
= 3.0V
V
OUT
= 0.5V, V
DD
= 5.0V
Source
Transient Characteristics.
(T
A
= -25˚C to +85˚C, V
DD
= 5V ± 10%)
Parameter
(See Fig. 2 & 3)
SCK High Pulse Width
SCK Low Pulse Width
SS/ Set Up Time
SS/ Hold Time
Quadrature Mode
(See Fig. 4, 6 & 7)
f
CKI
High Pulse Width
f
CKI
Pulse Width
f
CKI
Frequency
Effective Filter Clock f
F
Period
Effective Filter Clock f
F
frequency
Quadrature Separation
Quadrature Clock Pulse Width
Quadrature Clock frequency
Quadrature Clock to Count Delay
x1 / x2 / x4 Count Clock Pulse Width
Index Input Pulse Width
Index Set Up Time
Index Hold Time
Quadrature clock to
DFLAG/ or LFLAG/ delay
DFLAG/ output width
7366-111805-5
Symbol
t
CH
t
CL
t
CSL
t
CSH
Min. Value
100
100
100
100
Max.Value
-
-
-
-
Unit
ns
ns
ns
ns
Remarks
-
-
-
-
t
1
t
2
f
FCK
t
3
t
3
f
F
t
4
t
5
f
QA
, f
QB
t
Q1
t
Q2
t
id
t
is
t
ih
t
fl
t
fw
12
12
-
25
50
-
26
52
-
4t
3
12
32
-
-
4.5t
3
26
-
-
40
-
-
40
-
-
9.6
5t
3
-
-
5
5
5.5t
3
-
ns
ns
MHz
ns
ns
MHz
ns
ns
MHz
-
ns
ns
ns
ns
ns
ns
-
-
-
t
3
= t
1
+t
2
, MDR0 <7> = 0
t
3
= 2(t
1
+t
2
), MDR0 <7> = 1
f
F
= 1/t
3
t
4
> t
3
t
5
≥
2
t3
f
QA
= f
QB
< 1/4t
3
-
t
Q2
= (t
3
)/2
t
id
> t
4
-
-
-
t
fw
= t
4
Analog electronics
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