HFC-4S Cologne Chip AG, HFC-4S Datasheet - Page 248

• Manufacturer Part Number: HFC-4S
• Description: Isdn HDLC Fifo Controller With 8 (4) Integrated S/t Interfaces
• Manufacturer: Cologne Chip AG

HFC-4S
HFC-8S
13.1 GPIO and GPI functionality
Most of the interface signals can be used as general purpose I/O pins (GPIOs) or those who are only
inputs as general purpose input pins (GPIs). This functionality can be used if the pins are not used as
dedicated S/T interfaces.
GPIOs must be switched to GPIO mode in the register R_GPIO_SEL if they should be used as
outputs. The input functionality of all GPIOs and GPIs is allways enabled. The output values for the
GPIOs are set in the registers R_GPIO_OUT0 and R_GPIO_OUT1. The tristate function can be
enabled in the registers R_GPIO_EN0 and R_GPIO_EN1.
The input values for the GPIO[0..15] can be read in the registers R_GPIO_IN0 and R_GPIO_IN1.
The input values for GPI[0..31] can be read in the registers R_GPI_IN0, R_GPI_IN1, R_GPI_IN2
and R_GPI_IN3.
13.2 GPIO output voltage adjustment
The GPIO output high voltage can be influenced for each set of 4 GPIOs by connecting the appropiate
VDD_ST pin to a voltage different from VDD. The voltage must not exceed 3.6 V. See Table13.2 for
details.
248 of 273
General purpose I/O pins
Data Sheet
March 2003 (rev. A)
Cologne
Chip