SPRS742L June 2011 – February 2021 F28M35E20B , F28M35H22C , F28M35H52C , F28M35H52C-Q1 , F28M35M22C , F28M35M52C
PRODUCTION DATA
The ten pins of AIO_MUX2 can be selectively mapped through a dedicated set of registers to 12 analog inputs for ADC2 peripheral, six analog inputs for Comparator peripherals, four General-Purpose Inputs, or four General-Purpose Outputs. While AIO_MUX2 has been named after the analog signals passing through it, the GPIOs (here called AIOs) are still digital, although with fewer features than those in the GPIO_MUX1 and GPIO_MUX2 blocks—for example, they do not offer pullups. On reset, all pins of the AIO_MUX2 block are configured as analog inputs and the GPIO function is disabled. The AIO_MUX2 block is programmed through a separate set of registers from those used to program AIO_MUX1.
The multiple registers responsible for configuring the AIO_MUX2 pins are accessible by the C28x CPU only. The bottom portion of Figure 8-17 shows Control Subsystem registers and muxing logic for the associated ten AIO pins. The AIOMUX2 register selects one of ten possible analog input signals or one of four general-purpose AIO inputs. Other registers allow reading and writing of the four AIO bits, as well as setting the direction for each of the bits (read or write). See Table 8-32 for the mapping of analog inputs and AIOs to the ten pins of AIO_MUX2. Peripheral Modes 1 and 2 are currently not available.
AIO Mode 0 is chosen by setting selected odd bits of the AIOMUX2 register to ‘0’. AIO Mode 1 is chosen by setting selected odd bits of the AIOMUX2 register to ‘1’. For example, setting bit 9 of the AIOMUX2 register to ‘0’ assigns pin ADC2INA4 to internal signal AIO20 (digital GPIO). Setting bit 9 of the AIOMUX2 register to ‘1’ assigns pin ADC2INA4 to analog inputs ADC2INA4 or COMPA5 (only one should be enabled at a time in the respective analog module). Currently, all even bits of the AIOMUX2 register are “don’t cares”.
DEVICE PIN NAME(1)(2) | C28x AIO MODE 0(3) | C28x AIO MODE 1(4) |
---|---|---|
ADC2INA0 | – | ADC2INA0 |
ADC2INA2 | AIO18 | ADC2INA2, COMPA4 |
ADC2INA3 | – | ADC2INA3 |
ADC2INA4 | AIO20 | ADC2INA4, COMPA5 |
ADC2INA6 | AIO22 | ADC2INA6, COMPA6 |
ADC2INA7 | – | ADC2INA7 |
ADC2INB0 | – | ADC2INB0 |
ADC2INB3 | – | ADC2INB3 |
ADC2INB4 | AIO28 | ADC2INB4, COMPB5 |
ADC2INB7 | – | ADC2INB7 |