
III PERIPHERAL BLOCK: INPUT/OUTPUT PORTS
B-III-9-8
EPSON
S1C33L01 FUNCTION PART
P07D–P00D: P0[7:0] I/O port data (D[7:0]) / P0 I/O port data register (0x402D1)
P16D–P10D: P1[6:0] I/O port data (D[6:0]) / P1 I/O port data register (0x402D5)
P27D–P20D: P2[7:0] I/O port data (D[7:0]) / P2 I/O port data register (0x402D9)
P35D–P30D: P3[5:0] I/O port data (D[5:0]) / P3 I/O port data register (0x402DD)
This register reads data from I/O-port pins or sets output data.
When writing data
Write "1": High level
Write "0": Low level
When an I/O port is set for output, the data written to it is directly output to the I/O port pin. If the data written to the
port is "1", the port pin is set high (VDD and VDDE level); if the data is "0", the port pin is set low (VSS level).
Even in the input mode, data can be written to the port data register.
When reading data
Read "1": High level
Read "0": Low level
The voltage level on the port pin is read out regardless of whether an I/O port is set for input or output mode.If the pin
voltage is high (VDD and VDDE level), "1" is read out as input data; if the pin voltage is low (VSS level), "0" is read out
as input data.
At cold start, all data bits are set to "0". At hot start, they retain their state from prior to the initial reset.
IOC07–IOC00: P0[7:0] port I/O control (D[7:0]) / P0 port I/O control register (0x402D2)
IOC16–IOC10: P1[6:0] port I/O control (D[6:0]) / P1 port I/O control register (0x402D6)
IOC27–IOC20: P2[7:0] port I/O control (D[7:0]) / P2 port I/O control register (0x402DA)
IOC35–IOC30: P3[5:0] port I/O control (D[5:0]) / P3 port I/O control register (0x402DE)
Directs an I/O port for input or output.
Write "1": Output mode
Write "0": Input mode
Read: Valid
This I/O control register corresponds bit-for-bit to each I/O port. When an IOC bit is set to "1", the corresponding I/O
port is directed for output; if it is set to "0", the I/O port is directed for input.
At cold start, all IOC bits are set to "0" (input). At hot start, IOC retains its state from prior to the initial reset.
If pins P10–P13, P15–P16, P30 and P34 are set for use with peripheral circuits, their pin functions vary depending
on the input/output direction control by the IOC1x register.