Intel 80C196NU, 8XC196NP, Microcontroller manual CCR0

Models: Microcontroller 80C196NU 8XC196NP

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REGISTERS

CCR0

CCR0

no direct access

The chip configuration 0 (CCR0) register enables or disables powerdown and standby (80C196NU only) modes and selects the write-control mode. It also contains the bus-control parameters for fetching chip configuration byte 1.

7

1

1

WS1

WS0

 

 

 

 

0

DEMUX

BHE#

BW16

PD

 

 

 

 

Bit

Bit

 

 

Function

Number

Mnemonic

 

 

 

 

 

 

 

 

7:6

1

To guarantee device operation, write ones to these bits.

 

 

 

 

5:4

WS1:0

Wait States

 

 

 

These two bits control the number of wait states that are used for an

 

 

external fetch of CCB1.

 

 

WS0 WS1

 

 

 

0

0

zero wait states

 

 

0

1

one wait state

 

 

1

0

two wait states

 

 

1

1

three wait states

 

 

 

3

DEMUX

Select Demultiplexed Bus

 

 

Selects the demultiplexed bus mode for an external fetch of CCB1:

 

 

0

= multiplexed — address and data are multiplexed on AD15:0.

 

 

1

= demultiplexed — data only on AD15:0.

 

 

 

2

BHE#

Write-control Mode

 

 

Selects the write-control mode, which determines the functions of the

 

 

BHE#/WRH# and WR#/WRL# pins for external bus cycles:

 

 

0

= write strobe mode: the BHE#/WRH# pin operates as WRH#, and the

 

 

 

WR#/WRL# pin operates as WRL#.

 

 

1

= standard write-control mode: the BHE#/WRH# pin operates as

 

 

 

BHE#, and the WR#/WRL# pin operates as WR#.

 

 

 

1

BW16

Buswidth Control

 

 

Selects the bus width for an external fetch of CCB1:

 

 

0

= 8-bit bus

 

 

 

1

= 16-bit bus

 

 

 

 

0

PD

Powerdown Enable

 

 

Enables or disables the IDLPD #2 and IDLPD #3 instructions. When

 

 

enabled, the IDLPD #2 instruction causes the microcontroller to enter

 

 

powerdown mode and for the 80C196NU only, the IDLPD #3 instruction

 

 

causes the microcontroller to enter standby mode.

 

 

0

= disable powerdown and standby modes

 

 

1

= enable powerdown and standby modes

 

 

If your design uses powerdown or standby mode, set this bit when you

 

 

program the CCBs. If it does not, clearing this bit when you program the

 

 

CCBs will prevent accidental entry into powerdown and standby mode.

 

 

(Chapter 12, “Special Operating Modes,” discusses powerdown and

 

 

standby modes.)

 

 

 

 

 

 

The CCRs are loaded with the contents of the chip configuration bytes (CCBs) after a device reset. The CCBs reside in nonvolatile memory at addresses FF2018H (CCB0) and FF201AH (CCB1).

C-11

Page 402
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Intel 80C196NU, 8XC196NP, Microcontroller manual CCR0