Chapter 11 System Integration Unit Lite (SIUL)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
259
11.6
Functional description
11.6.1
General
This section provides a functional description of the System Integration Unit Lite.
11.6.2
Pad control
The SIUL controls the configuration and electrical characteristic of the device pads. It provides a
consistent interface for all pads, both on a by-port and a by-bit basis. The SIUL allows each pad to be
configured as either a General Purpose Input Output pad (GPIO), and as one or more alternate functions
(input or output). The pad configuration registers (PCR
n
, see
Section 11.5.2.8, “Pad Configuration
) allow software control of the static electrical characteristics of external pins with
a single write. These configure the following pad features:
•
Open drain output enable
•
Slew rate control
•
Pull control
•
Pad assignment
•
Control of analog path switches
•
Safe mode behavior configuration
11.6.3
General purpose input and output pads (GPIO)
The SIUL allows each pad to be configured as either a General Purpose Input Output pad (GPIO), and as
one or more alternate functions (input or output), the function of which is normally determined by the
peripheral that uses the pad.
The SIUL manages up to 64 GPIO pads organized as ports that can be accessed for data reads and writes
as 32-bit, 16-bit or 8-bit.
As shown in
, all port accesses are identical with each read or write being performed only at
a different location to access a different port width.
Figure 11-19. Data port example arrangement showing configuration for different port width accesses
This implementation requires that the registers are arranged in such a way as to support this range of port
widths without having to split reads or writes into multiple accesses.
31
23
15
7
0
SIUL Base +
15
7
0
SIUL Base +
15
7
0
SIUL Base +
7
0
0x0003
SIUL Base +
7
0
0x0002
SIUL Base +
7
0
0x0001
SIUL Base +
7
0
0x0000
0x0002
0x0000
32-bit Port
16-bit Port
16-bit Port
8-bit Port
8-bit Port
8-bit Port
8-bit Port
SIUL Base + 0x0000