C8051F85X86X Datasheet, PDF (175/290 Pages) Silicon Laboratories – Low-Cost 8-bit MCU Family with up to 8 kB of Flash

C8051F85x/86x
21.2.3. Assigning Port I/O Pins to Fixed Digital Functions
Fixed digital functions include external clock input as well as external event trigger functions, which can be used to
trigger events such as an ADC conversion, fire an interrupt or wake the device from idle mode when a transition
occurs on a digital I/O pin. The fixed digital functions do not require dedicated pins and will function on both GPIO
pins and pins in use by the crossbar. Fixed digital functions cannot be used on pins configured for analog I/O.
Table 21.3 shows all available fixed digital functions and the potential mapping of port I/O to each function.
Table 21.3. Port I/O Assignment for Fixed Digital Functions
Function
External Interrupt 0
External Interrupt 1
Potentially Assignable Port Pins
P0.0 - P0.7
P0.0 - P0.7
SFR(s) used for
Assignment
IT01CF
IT01CF
Conversion Start (CNVSTR)
P0.6
ADC0CN
External Clock Input (EXTCLK)
P0.3
OSCXCN
Port Match
P0.0 - P1.7
P0MASK, P0MAT
P1MASK, P1MAT
Preliminary Rev 0.6
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