8XC196LX SUPPLEMENT

USFR1 (read only)

Address:

1FF2H

 

Reset State:

XXH

The UPROM special-function register 1 (USFR1) reflects the status of unerasable, programmable read-only memory (UPROM) locations. This read-only register reflects the status of two bits that control the output frequency on CLKOUT.

7

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

CLK1

CLK0

 

 

 

 

 

 

 

 

 

 

 

 

Bit

Bit

 

 

 

 

 

 

Function

 

 

Number

Mnemonic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7:2

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1:0

CLK1:0

CLKOUT Control

 

 

 

 

 

 

 

 

These bits reflect the programmed frequency of the CLKOUT signal:

 

 

CLK1 CLK0

 

 

 

 

 

 

 

 

 

0

0

 

divide by 1 (CLKOUT = f/2)

 

 

 

 

0

1

 

divide by 2 (CLKOUT = f/4)

 

 

 

 

1

0

 

divide by 4 (CLKOUT = f/8)

 

 

 

 

1

1

 

divide by 1 (CLKOUT = f/2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2-5. Unerasable PROM 1 (USFR1) Register (LA, LB Only)

To program these bits, write the correct value to the locations shown in Table 2-4 using slave pro- gramming mode. During normal operation, you can determine the values of these bits by reading the UPROM SFR (Figure 2-5).

You can verify a UPROM bit to make sure it programmed, but you cannot erase it. For this rea- son, Intel cannot test the bits before shipment. However, Intel does test the features that the UP- ROM bits enable, so the only undetectable defects are (unlikely) defects within the UPROM cells themselves.

Table 2-4. UPROM Programming Values and Locations

To set this bit

Write this value

To this location

 

 

 

CLK0

0001H

0768H

 

 

 

CLK1

0002H

0728H

 

 

 

2.5INTERNAL PERIPHERALS

The internal peripheral modules provide special functions for a variety of applications. This sec- tion provides a brief description of the peripherals that differ between the 8XC196Lx and the 8XC196Kx families.

2-6

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Intel 8XC196Jx, 8XC196Lx, 8XC196Kx, 87C196CA Internal Peripherals, Uprom Programming Values and Locations, CLK1 CLK0