Rainbow Electronics AT89C51SND1C - Manual (Page 8)

8
AT8xC51SND1C
4109E–8051–06/03
Table 6. MutiMediaCard Interface Signal Description
Table 7. UART Signal Description
Table 8. SPI Controller Signal Description
Table 9. TWI Controller Signal Description
Signal
Name Type Description
Alternate
Function
MCLK O
MMC Clock output
Data or command clock transfer.
-
MCMD I/O
MMC Command line
Bidirectional command channel used for card initialization and data
transfer commands. To avoid any parasitic current consumption,
unused MCMD input must be polarized to V
DD
or V
SS
.
-
MDAT I/O
MMC Data line
Bidirectional data channel. To avoid any parasitic current consumption,
unused MDAT input must be polarized to V
DD
or V
SS
.
-
Signal
Name Type Description
Alternate
Function
RXD I/O
Receive Serial Data
RXD sends and receives data in serial I/O mode 0 and receives data in
serial I/O modes 1, 2 and 3.
P3.0
TXD O
Transmit Serial Data
TXD outputs the shift clock in serial I/O mode 0 and transmits data in
serial I/O modes 1, 2 and 3.
P3.1
Signal
Name Type Description
Alternate
Function
MISO I/O
SPI Master Input Slave Output Data Line
When in master mode, MISO receives data from the slave peripheral.
When in slave mode, MISO outputs data to the master controller.
P4.0
MOSI I/O
SPI Master Output Slave Input Data Line
When in master mode, MOSI outputs data to the slave peripheral.
When in slave mode, MOSI receives data from the master controller.
P4.1
SCK I/O
SPI Clock Line
When in master mode, SCK outputs clock to the slave peripheral. When
in slave mode, SCK receives clock from the master controller.
P4.2
SS I
SPI Slave Select Line
When in controlled slave mode, SS enables the slave mode.
P4.3
Signal
Name Type Description
Alternate
Function
SCL I/O
TWI Serial Clock
When TWI controller is in master mode, SCL outputs the serial clock to
the slave peripherals. When TWI controller is in slave mode, SCL
receives clock from the master controller.
P1.6
SDA I/O
TWI Serial Data
SDA is the bidirectional Two Wire data line.
P1.7