24 I/O PORTS (GPIO)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
24-9
Input Port Noise Filters
24.6
The S1C33L26 provides noise filters to remove noise on the signals input from the ports shown below.
USI:
USI_DI, USI_CS, USI_CK
USIL:
USIL_DI, USIL_CS, USIL_CK
FSIO:
SIN0, SIN1, SCLK0, SCLK1, #SRDY0, #SRDY1
REMC: REMC_I
T16A5: T16A_EXCL_0, T16A_EXCL_1, T16A_ATMA_0, T16A_ATMA_1, T16A_ATMB_0, T16A_ATMB_1
ADC10: #ADTRIG
GPIO:
FPT0–FPTF interrupt ports (See note below.)
When using these noise filters, set ANFEN/GPIO_FILTER register to 1. When ANFEN is set to 0 (default), the in-
put signals bypass the noise filters.
Notes: • These noise filters cannot be enabled individually.
• The noise filters are not effective if these ports are used as general-purpose input port.
However, the noise filters for the general-purpose input ports that are selected as FPT inter-
rupt ports (FPT0 to FPTF) are effective.
• The GPIO_FILTER register is write-protected. Before the register can be rewritten, the write
protection must be removed by writing data 0x96 to PPROT[7:0]/GPIO_PROTECT register.
Bus Drive Control
24.7
The external data bus (D[15:0]) pins and the external address bus (A[25:0]) pins can be forcibly set to low level us-
ing LDRVDB/GPIO_BUS_DRV register and LDRVAD/GPIO_BUS_DRV register, respectively. This function is
useful when turning off the power of the external device connected to the bus.
When the control bit is set to 1, the corresponding bus signals go low. When the control bit is set to 0, the signal
control goes back to the SRAMC/SDRAMC.
Notes: • The low-drive control bit is disabled when the pin is used as a general-purpose I/O port (P
xy
).
• If the above bus signals are forcibly driven low when the CPU is running by the instructions
fetched from an external memory, the CPU will not be able to run after that point. To drive the
signals low, the CPU must be running with the program stored in the internal RAM.
Control Register Details
24.8
8.1 List of GPIO and Port MUX Registers
Table 24.
Address
Register name
Function
0x300300 GPIO_P0_DAT
P0 Port Data Register
P0 port input/output data
0x300301 GPIO_P0_IOC
P0 Port I/O Control Register
Control P0 port input/output direction
0x300302 GPIO_P1_DAT
P1 Port Data Register
P1 port input/output data
0x300303 GPIO_P1_IOC
P1 Port I/O Control Register
Control P1 port input/output direction
0x300304 GPIO_P2_DAT
P2 Port Data Register
P2 port input/output data
0x300305 GPIO_P2_IOC
P2 Port I/O Control Register
Control P2 port input/output direction
0x300306 GPIO_P3_DAT
P3 Port Data Register
P3 port input/output data
0x300307 GPIO_P3_IOC
P3 Port I/O Control Register
Control P3 port input/output direction
0x300308 GPIO_P4_DAT
P4 Port Data Register
P4 port input/output data
0x300309 GPIO_P4_IOC
P4 Port I/O Control Register
Control P4 port input/output direction
0x30030a GPIO_P5_DAT
P5 Port Data Register
P5 port input/output data
0x30030b GPIO_P5_IOC
P5 Port I/O Control Register
Control P5 port input/output direction
0x30030c GPIO_P6_DAT
P6 Port Data Register
P6 port input/output data
0x30030d GPIO_P6_IOC
P6 Port I/O Control Register
Control P6 port input/output direction
0x30030e GPIO_P7_DAT
P7 Port Data Register
P7 port input data
0x300310 GPIO_P8_DAT
P8 Port Data Register
P8 port input/output data
0x300311 GPIO_P8_IOC
P8 Port I/O Control Register
Control P8 port input/output direction
0x300312 GPIO_P9_DAT
P9 Port Data Register
P9 port input/output data
0x300313 GPIO_P9_IOC
P9 Port I/O Control Register
Control P9 port input/output direction
0x300314 GPIO_PA_DAT
PA Port Data Register
PA port input/output data