Datasheet

49Maxim Integrated
Quad Serial UART with 128-Word FIFOs
MAX14830
GPIOConfg—GPIO Configuration Register
Each UART has four GPIOs that can be configured as inputs or outputs and can be operated in push-pull or open-drain
mode. The reference clock must be active for the GPIOs to work.
Bits 7–4: GP[n]OD
Each UART has four individually assigned GPIO outputs as follows: UART0: GPIO0–GPIO3, UART1: GPIO4–GPIO7,
UART2: GPIO8–GPIO11, UART3: GPIO12–GPIO15. For example, for UART0: Bit 4 is GP0OD, Bit 5 is GP1OD, Bit 6 is
GP2OD, and Bit 7 is GP3OD (see Table 5).
Set GP[n]OD bits to 0 to configure the GPIO_s as push-pull outputs, if configured as outputs in GPIOConfg[3:0].
Set the GP[n]OD bits to 1 to configure to open-drain output operation.
When configured as inputs in GPIOConfg[3:0], the GPIO_s are high-impedance inputs with weak pulldowns.
Bits 3–0: GP[n]Out
Each UART has four individually assigned GPIO outputs as follows: UART0: GPIO0–GPIO3, UART1: GPIO4–GPIO7,
UART2: GPIO8–GPIO11, UART3: GPIO12–GPIO15. For example, for UART0: Bit 0 is GP0Out, Bit 1 is GP1Out, Bit 2 is
GP2Out, and Bit 3 is GP3Out (see Table 5).
The GP[n]Out bits configure the GPIO_ to be inputs or outputs. Set the GP[n]Out bits to 1 to configure the associated
GPIO_s as outputs. Set the GP[n]Out bits to 0 to configure the associated GPIOs as inputs.
Table 5. UART GPIO Assignments for GPIO Configuration
ADDRESS: 0x18
MODE: R/W
BIT 7 6 5 4 3 2 1 0
NAME
GP3OD GP2OD GP1OD GP0OD GP3Out GP2Out GP1Out GP0Out
RESET
0 0 0 0 0 0 0 0
UART GP3OD/GP3Out GP2OD/GP2Out GP1OD/GP1Out GP0OD/GP0Out
UART0 GPIO3 GPIO2 GPIO1 GPIO0
UART1 GPIO7 GPIO6 GPIO5 GPIO4
UART2 GPIO11 GPIO10 GPIO9 GPIO8
UART3 GPIO15 GPIO14 GPIO13 GPIO12