8XC196L
X SUPPLEMENT
9-2
9.2
DESIGN CONSIDERATIONS FOR 8XC196LA, LB, AND LD
With the exception of a few new multiplexed functions, the 8XC196Lx microcontrollers are pin
compatible with the 8XC196Jx microcontrollers. The 8XC196Jx microcontrollers are 52-lead
versions of 8XC196Kx microcontrollers.
Follow these recommendations to help maintain hardware and software compatibility between
the 8XC196Lx, 8XC196Kx, and future microcontrollers.
•
Bus width. Since the 8XC196Lx has neither a WRH# nor a BUSWIDTH pin, the
microcontroller cannot dynamically switch between 8- and 16-bit bus widths. Program the
CCBs to select 8-bit bus mode.
•
Wait states. Since the 8XC196Lx has no READY pin, the microcontroller cannot rely on a
READY signal to control wait states. Program the CCBs to limit the number of wait states
(0, 1, 2, or 3).
•
EPA6–EPA7. These functions exist in the 8XC196Lx, but the associated pins are omitted.
You can use these functions as software timers, to start A/D conversions (on 87C196LA
and LB only), or to reset the timers.
•
Slave port. Since the 8XC196Lx has no P5.1/SLPCS and P5.4/SLPINT pins, you cannot
use the slave port.
•
ONCE mode. On the 8XC196Lx, the ONCE mode entry function is multiplexed with P2.6
(and TXJ1850 on the 87C196LB) rather than with P5.4 as it is on the 8XC196Kx
(P5.4/SLPINT/ONCE).
•
NMI. Since the 8XC196Lx has no NMI pin, the nonmaskable interrupt is not supported.
Initialize the NMI vector (at location 203EH) to point to a RET instruction. This method
provides glitch protection only.
•
I/O ports. The following port pins do not exist in the 8XC196Lx: P0.0–P0.1, P1.4–P1.7,
P2.3 and P2.5, P5.1 and P5.4–P5.7, P6.2 and P6.3. Software can still read and write the
associated Px_REG, Px_MODE, and Px_DIR registers. Configure the registers for the
omitted pins as follows:
— Clear the corresponding Px_DIR bits. (Configures pins as complementary outputs.)
— Clear the corresponding Px_MODE bits. (Selects I/O port function.)
— Write either “0” or “1” to the corresponding Px_REG bits. (Effectively ties signals low
or high.)
Do not use the bits associated with the omitted port pins for conditional branch instructions.
Treat these bits as reserved.
•
Auto programming. During auto programming, the 8XC196Lx supports only a 16-bit,
zero-wait-state bus configuration.
Содержание 87C196CA
Страница 1: ...8XC196Lx Supplement to 8XC196Kx 8XC196Jx 87C196CA User s Manual August 2004 Order Number 272973 003...
Страница 9: ...1 Guide to This Manual...
Страница 10: ......
Страница 13: ...2 Architectural Overview...
Страница 14: ......
Страница 22: ......
Страница 23: ...3 Address Space...
Страница 24: ......
Страница 33: ...4 Standard and PTS Interrupts...
Страница 34: ......
Страница 43: ...5 I O Ports...
Страница 44: ......
Страница 51: ...6 Synchronous Serial I O Port...
Страница 52: ......
Страница 56: ......
Страница 57: ...7 Event Processor Array...
Страница 58: ......
Страница 65: ...8 J1850 Communications Controller...
Страница 66: ......
Страница 89: ...9 Minimum Hardware Considerations...
Страница 90: ......
Страница 93: ...10 Special Operating Modes...
Страница 94: ......
Страница 98: ......
Страница 99: ...11 Programming the Nonvolatile Memory...
Страница 100: ......
Страница 106: ......
Страница 107: ...A Signal Descriptions...
Страница 108: ......
Страница 118: ......
Страница 119: ...Glossary...
Страница 120: ......
Страница 133: ...Index...
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