Advanced Parallel I/O - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 316

• Port Input register (PTIL)
• Reduced Drive register (RDRL)
• Pull Device Enable register (PERL)
• Port Polarity Select register (PPSL)
The contents of these registers are identical to their equivalents in Port T. The functions of
Port L pins are shown in Figure 7.21.

PL0/FP16 (LCD frontplane pin 16)
PL1/FP17 (LCD frontplane pin 17)

PL2/FP18 (LCD frontplane pin 18)

PL3/FP19 (LCD frontplane pin 19)

PL4/FP28 (LCD frontplane pin 28)

PL5/FP29 (LCD frontplane pin 29)

PL6/FP30 (LCD frontplane pin 30)

PL7/FP31 (LCD frontplane pin 31)

Figure 7.21 ■ Port L pins and their alternate functions

7.5.10 Ports U, V, and W
These three ports are available in HCS12's H subfamily. In addition to being general
I/O ports, these three ports are provided for motor control. The following registers support the
operations of these three ports:
• Port I/O register (PTU, PTV, PTW)
• Port Data Direction register (DDRU, DDRV, DDRW)
• Port Input register (PTIU, PTIV, PTIW)
• Pull Device Enable register (PERU, PERV, PERW)
• Port Polarity Select register (PPSU, PPSV, PPSW)
• Port Slew Rate register (SRRU, SRRV, SRRW)
The functions of the first five of these registers are identical to their equivalents in Port L.
The contents of the Port Slew Rate register are illustrated in Figure 7.22.

7 6 5 4 3 2 1 0

Reset value
= 0x00

SRRx7 SRRx6 SRRx5 SRRx4 SRRx3 SRRx2 SRRx1 SRRx0

SRRx[7:0]: slew rate port x (x = U, V, or W)
0 = disable slew rate control.
1 = enable slew rate control.

Figure 7.22 ■ Port Slew Rate register (SRRU, SRRV, and SRRW)