PC912XDP512F0MPVR datasheet(843/1348 Pages) FREESCALE

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Chapter 22 DP512 Port Integration Module (S12XDP512PIMV2)

MC9S12XDP512 Data Sheet, Rev. 2.21

Freescale Semiconductor

845

22.3.2.25 Port S Data Direction Register (DDRS)

Read: Anytime.

Write: Anytime.

This register configures each port S pin as either input or output.

If SPI0 is enabled, the SPI0 determines the pin direction. Refer to SPI section for details.

If the associated SCI transmit or receive channel is enabled this register has no effect on the pins. The pin

is forced to be an output if a SCI transmit channel is enabled, it is forced to be an input if the SCI receive

channel is enabled.

The DDRS bits revert to controlling the I/O direction of a pin when the associated channel is disabled.

76543210

DDRS7

DDRS6

DDRS5

DDRS4

DDRS3

DDRS2

DDRS1

DDRS0

Reset

00000000

Figure 22-27. Port S Data Direction Register (DDRS)

Table 22-27. DDRS Field Descriptions

Field

Description

7–0

DDRS[7:0]

Data Direction Port S

0 Associated pin is conﬁgured as input.

1 Associated pin is conﬁgured as output.

Note: Due to internal synchronization circuits, it can take up to 2 bus clock cycles until the correct value is read

on PTS or PTIS registers, when changing the DDRS register.

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