Freescale Semiconductor MCF51QE128RM V1 ColdFire Rapid Gpio Functionality, Keyboard Interrupts

Chapter 6 Parallel Input/Output Control

The set/clear/toggle functionality allows software to affect an individual bit with a single write instruction, rather than using a read-modify-write sequence.

6.3.1Port Data Set Registers

The port data set registers (PTxSET) are write-only registers associated with ports C and E. Writing to these registers has the result: PortData = PortData SetPattern. A subsequent port data register (PTxD) read reflects the changed result.

6.3.2Port Data Clear Registers

The port data clear registers (PTxCLR) are write-only registers associated with ports C and E. Writing to these registers has the result: PortData = PortData && ~ClearPattern. A subsequent port data register (PTxD) read reflects the changed result.

6.3.3Port Data Toggle Register

The port data toggle registers (PTxTOG) are write-only registers associated with ports C & E. Writing to these registers has the result: PortData = PortData ^ TogglePattern. A subsequent port data register (PTxD) read reflects the changed result.

6.4V1 ColdFire Rapid GPIO Functionality

The set/clear/toggle functionality descibed in Section 6.3, “Port Data Set, Clear and Toggle Data Registers,” resides on the device peripheral bus. The V1 ColdFire core is capable of performing higher speed I/O via its local bus, which does not have latency penalties associated with the on-chip peripheral bus bridge. The Rapid GPIO module contains data, direction, and enable registers along with set, clear, and toggle registers, which are based at address 0x(00)C0_0000. This functionality can be programmed to take priority on ports C and E.

This functionality is further defined in Chapter 9, “Rapid GPIO (RGPIO)”.

6.5Keyboard Interrupts

Some port A, some port B, and all port D pins can be configured as keyboard interrupt inputs and as an external means of waking the MCU from stop or wait low-power modes. The block diagram for each keyboard interrupt logic is shown Figure 6-3.

MCF51QE128 MCU Series Reference Manual, Rev. 3

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