AT90S1200-4SC Atmel, AT90S1200-4SC Datasheet - Page 29

• Manufacturer Part Number: AT90S1200-4SC
• Description: MCU 1K ISP FLASH 4MHZ 20-SOIC
• Manufacturer: Atmel
• Series: AVR® 90Sr

Specifications of AT90S1200-4SC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SPI
• Peripherals: POR, WDT
• Number Of I /o: 15
• Program Memory Size: 1KB (512 x 16)
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Ram Size: -
• Data Converters: -

I/O Ports
Port B
Port B Data Register – PORTB
Port B Data Direction Register
– DDRB
Port B Input Pin Address –
PINB
0838H–AVR–03/02
All AVR ports have true Read-Modify-Write functionality when used as general digital
I/O ports. This means that the direction of one port pin can be changed without uninten-
tionally changing the direction of any other pin with the SBI and CBI instructions. The
same applies for changing drive value (if configured as output) or enabling/disabling of
pull-up resistors (if configured as input).
Port B is an 8-bit bi-directional I/O port.
Three I/O memory address locations are allocated for the Port B, one each for the Data
Register – PORTB ($18), Data Direction Register – DDRB ($17), and the Port B Input
Pins – PINB ($16). The Port B Input Pins address is read-only, while the Data Register
and the Data Direction Register are read/write.
All port pins have individually selectable pull-up resistors. The Port B output buffers can
sink 20 mA and thus drive LED displays directly. When pins PB0 to PB7 are used as
inputs and are externally pulled low, they will source current if the internal pull-up resis-
tors are activated.
The Port B pins with alternate functions are shown in Table 8.
Table 8. Port B Pin Alternate Functions
When the pins are used for the alternate function, the DDRB and PORTB register has to
be set according to the alternate function description.
The Port B Input Pins address (PINB) is not a register, and this address enables access
to the physical value on each Port B pin. When reading PORTB, the Port B Data Latch
is read, and when reading PINB, the logical values present on the pins are read.
Bit
$18
Read/Write
Initial Value
Bit
$17
Read/Write
Initial Value
Bit
$16
Read/Write
Initial Value
Port Pin
PB0
PB1
PB5
PB6
PB7
PORTB7
PINB7
DDB7
R/W
R/W
N/A
R
7
0
7
0
7
Alternate Functions
AIN0 (Analog Comparator positive input)
AIN1 (Analog Comparator negative input)
MOSI (Data Input line for memory downloading)
MISO (Data Output line for memory uploading)
SCK (Serial Clock input)
PORTB6
PINB6
DDB6
R/W
R/W
N/A
R
6
0
6
0
6
PORTB5
PINB5
DDB5
R/W
R/W
N/A
R
5
0
5
0
5
PORTB4
PINB4
DDB4
R/W
R/W
N/A
R
4
0
4
0
4
PORTB3
PINB3
DDB3
R/W
R/W
N/A
R
3
0
3
0
3
PORTB2
PINB2
DDB2
R/W
R/W
N/A
R
2
0
2
0
2
PORTB1
PINB1
DDB1
R/W
R/W
N/A
R
AT90S1200
1
0
1
0
1
PORTB0
PINB0
DDB0
R/W
R/W
N/A
R
0
0
0
0
0
PORTB
DDRB
PINB
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