General-Purpose I/O
10-7
MPU/DSP Shared Peripherals
10.3 General-Purpose I/O
The GPIOs (see Figure 10–3) are programmable inputs or outputs. They gen-
erate a level interrupt, and the sources of this interrupt can be masked from
within the GPIO module. Under software control, the GPIOs can be individually
dedicated to either the DSP or the MPU.
GPIOs are general-purpose input and output external pins available to the
user for system-level control and general-purpose functions. The signals are
user-defined as either input or output. The output state can be controlled. And
inputs can be configured to provide an interrupt.
The MPU and the DSP have separate instances of the GPIO registers, but
share the same device pins. The determination of whether MPU or DSP has
control of the device pin is controlled by a single shared register, the pin control
register (at offset 0x18). In Figure 10–3 this register is shown as the configura-
tion and control register. This register is read/write from the MPU, but read-
only from the DSP. The MPU is responsible for writing to this register to assign
any necessary GPIO signals to the DSP. By default, all GPIO are assigned to
the MPU.
GPIO interrupts are routed to both the MPU and DSP interrupt handlers, but
a GPIO can only signal an interrupt to the processor to which it is assigned in
the pin control register. By default, GPIO interrupts are disabled at both of the
interrupt handlers.
There are no I/O signals associated with GPIO.5 and GPIO.10 interrupts.
10.3.1 Input/Outputs of the GPIO Module
Some GPIO signals are multiplexed with other peripheral functions. See
Appendix A, Input/Output Descriptions, for pin multiplexing information.
10.3.2 GPIO Port Registers
Table 10–2 lists the GPIO port registers. Table 10–3 through Table 10–10
describe the individual registers.
Each register exists both in the DSP GPIO and the MPU GPIO, except for the
pin control/pin status register.
Base Address: 0xFFFC:E000 (byte) for MPU; 0x0F000 (word) for DSP