Features
•
•
•
•
•
•
•
•
•
•
•
•
2-Kbyte ROM, 256
×
4-bit RAM
12 Bi-directional I/Os
Up to 6 External/Internal Interrupt Sources
Multifunction Timer/Counter with
– IR Remote Control Carrier Generator
– Bi-phase-, Manchester- and Pulse-width Modulator and Demodulator
Programmable System Clock with Prescaler and Five Different Clock Sources
Wide Supply-voltage Range (1.8 V to 6.5 V)
Very Low Sleep Current (< 1 µA)
32
×
16-bit EEPROM (ATAR890 only)
Synchronous Serial Interface (2-wire, 3-wire)
Watchdog, POR and Brown-out Function
Voltage Monitoring Inclusive Lo_BAT Detection
Flash Controller ATAM893 Available (SSO20)
Description
The ATAR090 and ATAR890 are members of Atmel’s family of 4-bit single-chip micro-
controllers. They offer the highest integration for IR and RF data communication and
remote-control. The ATAR090 and ATAR890 are suitable for the transmitter side. They
contain ROM, RAM, parallel I/O por ts, two 8-bit programmable multifunction
timer/counters with modulator and demodulator function, voltage supervisor, interval
timer with watchdog function and a sophisticated on-chip clock generation with exter-
nal clock input, integrated RC-, 32-kHz crystal- and 4-MHz crystal-oscillators. The
ATAR890 has an additional EEPROM as a second chip in one package.
Figure 1.
Block Diagram
V
SS
V
DD
OSC1 OSC2
Low-current
Microcontroller
for Wireless
Communication
ATAR090
ATAR890
Brown-out protect
RESET
Voltage monitor
External input
VMI
Crystal
External
RC
oscillators oscillators clock input
Clock management
UTCM
Timer 1
interval- and
watchdog timer
ROM
2 K x 8 bit
RAM
256 x 4 bit
Timer 2
8/12-bit timer
with modulator
SSI
Serial interface
T2I
T2O
SD
SC
Data direction
BP20/NTE
Port 2
BP21
BP22
BP23
MARC4
4-bit CPU core
I/O bus
Data direction +
alternate function
Port 4
Data direction +
interrupt control
Port 5
BP42
BP40
T2O
INT3
SC BP41
BP43
INT3
VMI
SD
T2I
BP52
BP50
INT6
INT1
BP53
BP51
INT1
INT6
Rev. 4696D–4BMCU–12/04
Pin Configuration
Figure 2.
Pinning SSO20
VDD
BP40/INT3/SC
BP53/INT1
BP52/INT1
BP51/INT6
BP50/INT6
OSC1
OSC2
NC
NC
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VSS
BP43/INT3/SD
BP42/T2O
BP41/VMI/T2I
BP23
BP22
BP21
BP20/NTE
NC
NC
Pin Description
Name
VDD
VSS
NC
NC
BP20
BP21
BP22
BP23
BP40
BP41
BP42
BP43
BP50
BP51
BP52
BP53
NC
NC
OSC1
Type
–
–
–
–
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
–
–
I
Function
Supply voltage
Circuit ground
Not connected
Not connected
Bi-directional I/O line of Port 2.0
Bi-directional I/O line of Port 2.1
Bi-directional I/O line of Port 2.2
Bi-directional I/O line of Port 2.3
Bi-directional I/O line of Port 4.0
Bi-directional I/O line of Port 4.1
Bi-directional I/O line of Port 4.2
Bi-directional I/O line of Port 4.3
Bi-directional I/O line of Port 5.0
Bi-directional I/O line of Port 5.1
Bi-directional I/O line of Port 5.2
Bi-directional I/O line of Port 5.3
Not connected
Not connected
Oscillator input
Alternate Function
–
–
–
–
NTE – test mode enable, see section “Master Reset”
–
–
–
SC serial clock or INT3 external interrupt input
VMI voltage monitor input or T2I external clock input
Timer 2
T2O Timer 2 output
SD serial data I/O or INT3-external interrupt input
INT6 external interrupt input
INT6 external interrupt input
INT1 external interrupt input
INT1 external interrupt input
–
–
4-MHz crystal input or 32-kHz crystal input or
external clock input or external trimming resistor
input
4-MHz crystal output or 32-kHz crystal output or
external clock input
Pin No.
1
20
10
11
13
14
15
16
2
17
18
19
6
5
4
3
9
12
7
Reset State
NA
NA
–
–
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
–
–
Input
OSC2
O
Oscillator output
8
NA
2
ATAR090/ATAR890
4696D–4BMCU–12/04
ATAR090/ATAR890
Introduction
The ATAR090/ATAR890 are members of Atmel’s family of 4-bit single-chip microcon-
trollers. They contain ROM, RAM, parallel I/O ports, one 8-bit programmable multi-
function timer/counters, voltage supervisor, interval timer with watchdog function and a
sophisticated on-chip clock generation with integrated RC-, 32-kHz crystal- and 4-MHz
crystal oscillators. Table 2 provides an overview of the available variants.
Table 1.
Available Variants of ATAxx9x
Version
Flash device
Production
Production
Type
ATAM893
ATAR090
ATAR890
ROM
4-Kbyte EEPROM
2-Kbyte mask ROM
2-Kbyte mask ROM
E2PROM Peripheral
64 byte
–
64 byte
Packages
SSO20
SSO20
SSO20
MARC4 Architecture
General Description
The MARC4 microcontroller consists of an advanced stack-based, 4-bit CPU core and
on-chip peripherals. The CPU is based on the HARVARD architecture with physically
separate program memory (ROM) and data memory (RAM). Three independent buses,
the instruction bus, the memory bus and the I/O bus, are used for parallel communica-
tion between ROM, RAM and peripherals. This enhances program execution speed by
allowing both instruction prefetching, and a simultaneous communication to the on-chip
peripheral circuitry. The extremely powerful integrated interrupt controller with associ-
ated eight prioritized interrupt levels supports fast and efficient processing of hardware
events. The MARC4 is designed for the high-level programming language qFORTH.
The core includes both an expression and a return stack. This architecture enables
high-level language programming without any loss of efficiency or code density.
Figure 3.
MARC4 Core
MARC4 CORE
Reset
Program
memory
PC
X
Y
SP
RP
RAM
256 x 4-bit
Reset
Clock
Instruction
bus
Instruction
decoder
Memory bus
TOS
CCR
System
clock
Sleep
Interrupt
controller
I/O bus
ALU
On-chip peripheral modules
3
4696D–4BMCU–12/04
Components of MARC4
Core
ROM
The core contains ROM, RAM, ALU, program counter, RAM address registers, instruc-
tion decoder and interrupt controller. The following sections describe each functional
block in more detail.
The program memory (ROM) is mask programmed with the customer application pro-
gram during fabrication of the microcontroller. The 2 Kbyte ROM size is addressed by a
12-bit wide program counter. An additional 1 Kbyte of ROM exists which is reserved for
quality control self-test software The lowest user ROM address segment is taken up by
a 512-byte zero page which contains predefined start addresses for interrupt service
routines and special subroutines accessible with single byte instructions (SCALL).
The corresponding memory map is shown in Figure 4 Look-up tables of constants can
also be held in ROM and are accessed via the MARC4’s built-in table instruction.
Figure 4.
ROM Map
7FFh
1F8h
1F0h
1E8h
1E0h
1 E0h
1C 0h
180h
I NT 7
I NT 6
I NT 5
I NT 4
I NT 3
I NT 2
I NT 1
I NT 0
SCALL addresses
ROM
(2 K x 8 bit)
Z er o
p age
140h
100h
0C 0h
080h
040h
1FFh
Zero page
000h
020 h
018h
010h
008h
000 h
008h
000h
$R E SE T
$A U T O SL E E P
RAM
The ATAR090 and ATAR890 contain 256 x 4-bit wide static random access memory
(RAM). It is used for the expression stack, the return stack and data memory for vari-
ables and arrays. The RAM is addressed by any of the four 8-bit wide RAM address
registers SP, RP, X and Y.
The 4-bit wide expression stack is addressed with the expression stack pointer (SP). All
arithmetic, I/O and memory reference operations take their operands from, and return
their results to the expression stack. The MARC4 performs the operations with the top of
stack items (TOS and TOS-1). The TOS register contains the top element of the expres-
sion stack and works in the same way as an accumulator. This stack is also used for
passing parameters between subroutines and as a scratch pad area for temporary stor-
age of data.
The 12-bit wide return stack is addressed by the return stack pointer (RP). It is used for
storing return addresses of subroutines, interrupt routines and for keeping loop index
counts. The return stack can also be used as a temporary storage area.
The MARC4 instruction set supports the exchange of data between the top elements of
the expression stack and the return stack. The two stacks within the RAM have a user
definable location and maximum depth.
Expression Stack
Return Stack
4
ATAR090/ATAR890
4696D–4BMCU–12/04
ATAR090/ATAR890
Figure 5.
RAM Map
RAM
(256 x 4-bit)
Autosleep
FCh
FFh
Global
variables
Expression stack
3
0
SP
TOS
TOS-1
TOS-2
4-bit
Expression
stack
Return
stack
RAM address register:
X
Y
Return stack
11
0
RP
SP
TOS-1
RP
04h
00h
07h
03h
Global
v
variables
12-bit
Registers
The MARC4 controller has seven programmable registers and one condition code regis-
ter. They are shown in the following programming model (see Figure 6).
The program counter is a 12-bit register which contains the address of the next instruc-
tion to be fetched from ROM. Instructions currently being executed are decoded in the
instruction decoder to determine the internal micro-operations. For linear code (no calls
or branches) the program counter is incremented with every instruction cycle. If a
branch-, call-, return-instruction or an interrupt is executed, the program counter is
loaded with a new address. The program counter is also used with the table instruction
to fetch 8-bit wide ROM constants.
Figure 6.
Programming Model
11
0
Program Counter (PC)
PC
7
0
Program counter
RP
7
0
0
0
Return stack pointer
SP
7
0
Expression stack pointer
X
7
0
RAM address register (X)
Y
3
0
RAM address register (Y)
TOS
3
0
Top of stack register
CCR
C
--
B
I
Condition code register
Interrupt enable
Branch
Reserved
Carry/borrow
5
4696D–4BMCU–12/04
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