AT90S8515

Manufacturer Part NumberAT90S8515
Description8-bit microcontroller with 8K bytes in-system programmable flash, 2.7-6.0V
ManufacturerATMEL Corporation
AT90S8515 datasheet
 
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Page 70/112:

Port C

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Port C

Port C Data Register – PORTC
AT90S8515
70
Figure 51. Port B Schematic Diagram (Pin PB7)
MOS
PULL-
UP
PB7
WRITE PORTB
WP:
WD:
WRITE DDRB
RL:
READ PORTB LATCH
RP:
READ PORTB PIN
READ DDRB
RD:
SPE:
SPI ENABLE
MSTR
MASTER SELECT
Port C is an 8-bit bi-directional I/O port. Three I/O memory address locations are allo-
cated for the Port C, one each for the Data Register – PORTC, $15($35), Data Direction
Register – DDRC, $14($34) and the Port C Input Pins – PINC, $13($33). The Port C
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 C output buffers can
sink 20 mA and thus drive LED displays directly. When pins PC0 to PC7 are used as
inputs and are externally pulled low, they will source current if the internal pull-up resis-
tors are activated.
The Port C pins have alternate functions related to the optional external data SRAM.
Port C can be configured to be the high-order address byte during accesses to external
data memory. When Port C is set to the alternate function by the SRE (external SRAM
enable) bit in the MCUCR (MCU Control Register), the alternate settings override the
Data Direction Register.
Bit
7
6
5
$15 ($35)
PORTC7
PORTC6
PORTC5
Read/Write
R/W
R/W
R/W
Initial Value
0
0
0
RD
RESET
R
Q
D
DDB7
C
WD
RESET
R
Q
D
PORTB7
C
RL
WP
RP
MSTR
SPE
SPI CLOCK
OUT
SPI CLOCK
IN
4
3
2
1
PORTC4
PORTC3
PORTC2
PORTC1
PORTC0
R/W
R/W
R/W
R/W
0
0
0
0
0
PORTC
R/W
0
0841G–09/01