mc9s12hz256v2 Freescale Semiconductor, Inc, mc9s12hz256v2 Datasheet - Page 593

• Manufacturer Part Number: mc9s12hz256v2
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

21.3.2.12 External Bus Interface Control Register (EBICTL)
Read: Anytime (provided this register is in the map)
Write: Refer to individual bit descriptions below
The EBICTL register is used to control miscellaneous functions (i.e., stretching of external E clock).
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
Freescale Semiconductor
All other modes
RDRK
RDPE
RDPB
RDPA
ESTR
Field
Field
Peripheral
7
4
1
0
0
Reset:
W
R
Reduced Drive of Port K
0 All port K output pins have full drive enabled.
1 All port K output pins have reduced drive enabled.
Reduced Drive of Port E
0 All port E output pins have full drive enabled.
1 All port E output pins have reduced drive enabled.
Reduced Drive of Port B
0 All port B output pins have full drive enabled.
1 All port B output pins have reduced drive enabled.
Reduced Drive of Ports A
0 All port A output pins have full drive enabled.
1 All port A output pins have reduced drive enabled.
E Clock Stretches — This control bit determines whether the E clock behaves as a simple free-running clock or
as a bus control signal that is active only for external bus cycles.
Normal and Emulation: write once
Special: write anytime
0 E never stretches (always free running).
1 E stretches high during stretched external accesses and remains low during non-visible internal accesses.
This bit has no effect in single-chip modes.
7
0
0
0
Figure 21-16. External Bus Interface Control Register (EBICTL)
= Unimplemented or Reserved
6
0
0
0
Table 21-11. EBICTL Field Descriptions
Table 21-10. RDRIV Field Descriptions
MC9S12HZ256 Data Sheet, Rev. 2.05
5
0
0
0
Description
0
0
0
Description
4
Chapter 21 Multiplexed External Bus Interface (MEBIV3)
0
0
0
3
0
0
0
2
0
0
0
1
ESTR
0
1
0
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