Table 30-1 Pin Configuration; Pin Configuration Example Software; Programming Model; Table 30-2 Ssi Module Register Memory Map - Motorola DragonBall MC9328MX1 Reference Manual

Pin
SSI_RXFS Primary function of
GPIO Port C [3]
Alternate function
of GPIO Port B [14]
1. Only one of the two pins should be set-up for each SSI signal.

30.2.3.1 Pin Configuration Example Software

Code Example 30-1 sets up the SSI pins as the alternate function of Port B by following the configuration
in Table 30-1 on page 30-6.
// Configure Pad to Peripheral Function instead of GPIO
LDR r1,=GIUS_B
LDR r2,=0xFFF03FFF
STR r2,[r1]
// Configure Pad for Alternate Function instead of Primary
LDR r1,=GPR_B
LDR r2,=0x000FC000
STR r2,[r1]
// Configure FMCR to Select SSI input from SSI/SIM Pads
LDR r1,=FMCR
LDR r2,=0x000000F8
STR r2,[r1]
// The SSI default is in pull-up state. Disable the pull-up, making them tristate
LDR r1,=PUEN_B
LDR r2,=0xFFF03FFF
STR r2,[r1]

30.3 Programming Model

The SSI module includes ten user-accessible 32-bit registers. It also includes two 16-bit internal registers
×
and two 8 16 bit internal FIFOs. Table 30-2 summarizes these registers and their addresses.
MOTOROLA
Table 30-1. Pin Configuration (Continued)
1
Setting
1. Clear bit 3 of Port C GPIO In Use Register (GIUS_C)
2. Clear bit 3 of Port C General Purpose Register (GPR_C)
3. Clear bit 7 in the Function Muxing Control Register (FMCR) in
the System Control Module
1. Clear bit 14 of Port B GPIO In Use Register (GIUS_B)
2. Set bit 14 of Port B General Purpose Register (GPR_B)
3. Set bit 7 in the Function Muxing Control Register (FMCR) in
the System Control Module
Code Example 30-1. SSI Pin Setup
// GPIO PORT B GIUS register
// Pins 14-19 should be cleared
// GPIO PORT B GPR register
// Pins 14-19 should be set
// CRM FMCR register
// Pins 7-3 should be set
// GPIO PORTB PUEN register
// Disable pullup for SSI input pins
Table 30-2. SSI Module Register Memory Map
Description
SSI Transmit Data Register
SSI Receive Data Register
SSI Control/Status Register
Synchronous Serial Interface (SSI)
Configuration Procedure
Name Address
STX 0x00218000
SRX 0x00218004
SCSR 0x00218008
Programming Model
30-7