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Chapter 7
Parallel input/output
7.1 Introduction
This device has three sets of I/O ports, which include up to 18 general-purpose I/O pins.
Not all pins are available on all devices. See to determine which functions are available
for a specific device.
Many of the I/O pins are shared with on-chip peripheral functions, as shown in . The
peripheral modules have priority over the I/O, so when a peripheral is enabled, the
associated I/O functions are disabled.
After reset, the shared peripheral functions are disabled so that the pins are controlled by
the parallel I/O except PTA4 and PTA5 that are default to BKGD/MS and RESET
function. All of the parallel I/O are configured as high-impedance (Hi-Z). The pin control
functions for each pin are configured as follows:
• input disabled (PTxIEn = 0),
• output disabled (PTxOEn = 0), and
• internal pullups disabled (PTxPEn = 0).
Additionally, the parallel I/O that support high drive capability are disabled (HDRVE =
0x00) after reset.
The following three figures show the structures of each I/O pin.
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
NXP Semiconductors
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Summary of Contents for MC9S08PA4
Page 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Page 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Page 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Page 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Page 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Page 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Page 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Page 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Page 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Page 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Page 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
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