Datasheet

Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E128 Data Sheet, Rev. 1.07
530 Freescale Semiconductor
18.3.2.10 Pull Control Register (PUCR)
Read: Anytime (provided this register is in the map).
Write: Anytime (provided this register is in the map).
This register is used to select pull resistors for the pins associated with the core ports. Pull resistors are
assigned on a per-port basis and apply to any pin in the corresponding port that is currently configured as
an input. The polarity of these pull resistors is determined by chip integration. Please refer to the device
overview chapter to determine the polarity of these resistors.
Table 18-8. MODC, MODB, and MODA Write Capability
a
a
No writes to the MOD bits are allowed while operating in a secure mode. For more details, refer to the device
overview chapter.
MODC MODB MODA Mode MODx Write Capability
0 0 0 Special single chip MODC, MODB, and MODA
write anytime but not to 110
b
b
If you are in a special single-chip or special test mode and you write to this register, changing to normal sin-
gle-chip mode, then one allowed write to this register remains. If you write to normal expanded or emulation
mode, then no writes remain.
0 0 1 Emulation narrow No write
0 1 0 Special test MODC, MODB, and MODA
write anytime but not to 110
(2)
0 1 1 Emulation wide No write
1 0 0 Normal single chip MODC write never,
MODB and MODA write once
but not to 110
1 0 1 Normal expanded narrow No write
1 1 0 Special peripheral No write
1 1 1 Normal expanded wide No write
76543210
R
PUPKE
00
PUPEE
00
PUPBE PUPAE
W
Reset
1
10010000
NOTES:
1. The default value of this parameter is shown. Please refer to the device overview chapter to deter-
mine the actual reset state of this register.
= Unimplemented or Reserved
Figure 18-14. Pull Control Register (PUCR)