Pio user interface – Rainbow Electronics AT75C220 User Manual
Page 66

AT75C220
66
PIO User Interface
PIO Controller A Base Address: 0xFF00C000
PIO Controller B Base Address: 0xFF010000
Notes:
1. The reset value of this register depends on the level of the external pins at reset.
2. This register is cleared at reset. However, the first read of the register can give a value not equal to zero if any changes have
occurred on any pins between the reset and the read.
Table 21. PIO Controller Memory Map
Offset
Register Name
Description
Access
Reset Value
0x00
PIO_PER
PIO Enable Register
Write-only
–
0x04
PIO_PDR
PIO Disable Register
Write-only
–
0x08
PIO_PSR
PIO Status Register
Read-only
–
0x0C
–
Reserved
–
–
0x10
PIO_OER
Output Enable Register
Write-only
–
0x14
PIO_ODR
Output Disable Register
Write-only
–
0x18
PIO_OSR
Output Status Register
Read-only
0x0
0x1C
–
Reserved
–
–
0x20
–
Reserved
–
–
0x24
–
Reserved
–
–
0x28
–
Reserved
–
0x0
0x2C
–
Reserved
–
–
0x30
PIO_SODR
Set Output Data Register
Write-only
–
0x34
PIO_CODR
Clear Output Data Register
Write-only
–
0x38
PIO_ODSR
Output Data Status Register
Read-only
0x0
0x3C
PIO_PDSR
Pin Data Status Register
Read-only
See Note 1
0x40
PIO_IER
Interrupt Enable Register
Write-only
–
0x44
PIO_IDR
Interrupt Disable Register
Write-only
–
0x48
PIO_IMR
Interrupt Mask Register
Read-only
–
0x4C
PIO_ISR
Interrupt Status Register
Read-only
See Note 2