Datasheet
16 Maxim Integrated
Quad Serial UART with 128-Word FIFOs
MAX14830
Pin Description (continued)
PIN NAME FUNCTION
9 V
L
Digital Interface Logic-Level Supply. V
L
powers the internal logic-level translators for RST, IRQ, MOSI/
A1, CS/A0, SCLK/SCL, MISO/SDA, LDOEN, and SPI/I2C. Bypass V
L
with a 0.1FF ceramic capacitor to
DGND.
10 DGND Digital Ground
11 GPIO0
General-Purpose Input/Output 0. GPIO0 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO0 has a weak pulldown resistor to ground. GPIO0 is the
reference clock output when bit 7 of the TxSynch register is set to 1 (see the UART Clock to GPIO sec-
tion for more information).
12 GPIO1
General-Purpose Input/Output 1. GPIO1 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO1 has a weak pulldown resistor to ground. GPIO1 is the
TIMER output when bit 7 of the TIMER2 register is set to 1.
13 GPIO2
General-Purpose Input/Output 2. GPIO2 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO2 has a weak pulldown resistor to ground.
14 GPIO3
General-Purpose Input/Output 3. GPIO3 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO3 has a weak pulldown resistor to ground.
15
RTS0
Active-Low Request-to-Send Output for UART0. RTS0 can be set high or low by programming the LCR
register. RTS0 is the UART system clock/fractional divider output when bit 7 of the CLKSource register
is set to 1.
16
CTS0 Active-Low Clear-to-Send Input for UART0. CTS0 is a flow control status input.
17 RX0 Serial Receiving Data Input for UART0. RX0 has a weak pullup to V
EXT
.
18 TX0 Serial Transmitting Data Output for UART0
19 GPIO4
General-Purpose Input/Output 4. GPIO4 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO4 has a weak pulldown resistor to ground. GPIO4 is the
reference clock output when bit 7 of the TxSynch register is set to 1 (see the UART Clock to GPIO sec-
tion for more information).
20 GPIO5
General-Purpose Input/Output 5. GPIO5 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO5 has a weak pulldown resistor to ground. GPIO5 is the
TIMER output when bit 7 of the TIMER2 register is set to 1.
21 GPIO6
General-Purpose Input/Output 6. GPIO6 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO6 has a weak pulldown resistor to ground.
22 GPIO7
General-Purpose Input/Output 7. GPIO7 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO7 has a weak pulldown resistor to ground.
23
RTS1
Active-Low Request-to-Send Output for UART1. RTS1 can be set high or low by programming the LCR
register. RTS1 is the UART system clock/fractional divider output when bit 7 of the CLKSource register
is set to 1.
24
CTS1 Active-Low Clear-to-Send Input for UART1. CTS1 is a flow control status input.
25 RX1 Serial Receiving Data Input for UART1. RX1 has a weak pullup to V
EXT
.
26 TX1 Serial Transmitting Data Output for UART1
27 GPIO8
General-Purpose Input/Output 8. GPIO8 is user-programmable as an input or output (push-pull or open
drain) or external event interrupt source. GPIO8 has a weak pulldown resistor to ground. GPIO8 is the
reference clock output when bit 7 of the TxSynch register is set to 1 (see the UART Clock to GPIO sec-
tion for more information).