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8XC196Kx,8XC196Jx,87C196CA microcontroller family user's manual.1995.pdf
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8XC196Kx, Jx, CA USER’S MANUAL

 

VCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BUSWIDTH

 

 

 

 

 

CS#

 

CS#

 

 

AD15:8

 

 

 

 

74AC

A13:8

 

 

A12:7

A12:7

 

 

 

 

 

373

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ADV#

 

 

 

LE

 

 

 

D15:8

D7:0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8K×8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8XC196

 

 

 

 

 

 

8K×8

 

LE

 

 

 

RAM

 

RAM

 

 

 

 

 

 

 

 

 

 

 

 

(High)

 

(Low)

 

 

AD7:0

 

74AC

A7:1

 

 

 

 

 

 

 

 

A6:0

 

A6:0

 

 

 

373

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WE#

WE#

WRH#

WRL#

A3097-01

Figure 15-20. 16-bit System with RAM

15.7 BUS TIMING MODES (8XC196KS, KT ONLY)

The 8XC196KS, KT devices have selectable bus timing modes controlled by the MSEL0 and MSEL1 bits (bits 6 and 7) of CCR1. Figure 15-2 on page 15-7 defines these bit settings. The remainder of this section describes each mode. Figure 15-21 illustrates the modes together and Table 15-6 summarizes the differences in their timings.

15-30

INTERFACING WITH EXTERNAL MEMORY

TOSC

 

 

 

 

 

MODE 3

 

 

 

 

 

 

CLKOUT

 

 

 

 

 

 

ALE

 

 

 

 

 

 

RD#

 

 

 

 

 

 

 

 

 

 

TRLDV = 1 TOSC

 

TRHDZ = 1 TOSC

BUS

DATA

ADDR

DATA

ADDR

DATA

ADDR

 

 

 

 

TAVDV = 3 TOSC

 

 

ALE

 

 

 

 

 

MODE 0

 

 

 

 

 

 

RD#

 

 

TRLDV = 3 TOSC

 

 

 

 

 

TRHDZ = 1 TOSC

 

 

 

 

 

BUS

DATA

ADDR

 

DATA

ADDR

DATA

 

 

 

TAVDV = 5 TOSC

 

 

 

 

 

 

 

 

MODE 1

ALE

 

 

 

 

 

 

RD#

 

TRLDV = 2 TOSC

 

 

 

 

 

 

 

 

 

 

TRHDZ = 1 TOSC

 

BUS

DATA

ADDR

DATA

ADDR

DATA

ADDR

 

 

TAVDV = 3 TOSC

 

 

 

 

 

1/2 TOSC

 

 

 

MODE 2

 

 

TRLDV = 2 TOSC

 

 

 

 

 

 

 

 

 

 

 

TRHDZ = 1/2 TOSC

 

 

BUS

DATA

ADDR

DATA

ADDR

DATA

ADDR

 

 

TAVDV = 3.5 TOSC

 

 

 

 

 

 

 

 

 

A0311-02

 

 

Figure 15-21. Modes 0, 1, 2, and 3 Timings

 

15-31

8XC196Kx, Jx, CA USER’S MANUAL

Table 15-6. Modes 0, 1, 2, and 3 Timing Comparisons

Timing Specifications (in TOSC) Note 1

Mode

 

 

 

 

 

 

 

TCLLH

TCHLH

TAVLL

TAVDV

TRLRH

TRHDZ

TRLDV

 

Mode 3

0

N/A

1

3

1

1

1

 

 

 

 

 

 

 

 

Mode 0

0

N/A

1

5

3

1

3

 

 

 

 

 

 

 

 

Mode 1

N/A

0.5

0.5

3

2

1

2

 

 

 

 

 

 

 

 

Mode 2

N/A

0.5

1

3.5

2

0.5

2

 

 

 

 

 

 

 

 

NOTES:

1.These are ideal timing values for purposes of comparison only. They do not include internal device delays. Consult the data sheet for current device specifications.

2.N/A = This timing specification is not applicable in this mode.

15.7.1Mode 3, Standard Mode

Mode 3 is the standard timing mode. Use this mode for systems that need to emulate the 8XC196KR.

15.7.2 Mode 0, Standard Timing with One Automatic Wait State

Mode 0 is the standard timing mode with a minimum of one wait state added to each bus cycle.

The READY signal can be used to insert additional wait states, if necessary. The TRLDV and TAVDV timings are each 2 TOSC longer in mode 0 than in mode 3. The TRHDZ timing in mode 0 is the same as in mode 3.

15.7.3 Mode 1, Long Read/Write Mode

Mode 1 is the long read/write mode (Figure 15-22). In this mode, RD#, WR#, and ALE begin ½

TOSC earlier in the bus cycle and the width of RD# and WR# are 1 TOSC longer than in mode 3. The TRLDV timing is 1 TOSC longer in mode 1 than in mode 3, allowing the memory more time to get its data on the bus without the wait-state penalty of mode 0. The TAVDV and TRHDZ timing in mode 1 is the same as in mode 3.

15-32

INTERFACING WITH EXTERNAL MEMORY

 

 

TOSC

 

 

 

XTAL 1

 

 

 

 

 

 

TCHCL

 

TCLCL

 

TXHCH

 

 

 

 

CLKOUT

 

 

 

 

 

T

CHLH

 

TCLLL

 

 

 

 

TLHLH

 

 

 

 

 

ALE/ADV#

 

 

 

 

 

 

 

TLHLL

TLLRL

 

TRHLH

 

 

 

TRLRH

 

 

 

 

 

RD#

 

 

TRLDV

 

 

 

 

TAVLL

TRLAZ

 

 

 

 

TLLAX

 

TRHDZ

 

 

 

 

 

Bus Read

 

Address

Data In D15:0

 

AD15:0

 

 

 

 

 

 

 

8- and16-bit

 

 

TAVDV

 

 

Bus Mode

 

 

 

 

 

 

 

TLLWL

TWLWH

 

 

 

 

 

 

WR#

 

 

 

 

 

Bus Write

 

 

 

TQVWH

TWHQX

 

Address Out

Data Out

 

AD15:0

 

 

8- and 16-bit

 

 

 

 

TWHBX, TRHBX

Bus Mode

 

 

 

 

 

BHE#

 

 

BHE Valid

 

 

 

 

 

 

 

TWHAX, TRHAX

AD15:8

 

 

AD15:8 Valid 8-bit Bus Mode

 

 

 

 

 

 

TWHIX, TRHIX

INST

 

 

INST Valid

 

 

 

 

 

 

 

A3098-01

Figure 15-22. Mode 1 System Bus Timing

15.7.4 Mode 2, Long Read/Write with Early Address

 

Mode 2 (Figure 15-23) is similar to mode 1 in that RD#, WR#, and ALE begin ½ T

earlier in

OSC

 

the bus cycle and the widths of RD# and WR# are 1 TOSC longer than in mode 3. It differs from

mode 1 in that the address is also placed onto the bus ½ T

earlier in the bus cycle. The T

 

 

OSC

 

RLDV

timing is 1 T

longer, the T

timing is ½ T longer, and T

RHDZ

is ½ T shorter in mode 2

OSC

AVDV

OSC

 

OSC

than in mode 3. This mode trades a longer TAVDV for a shorter TRHDZ.

15-33

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