Internal Peripherals; Unerasable Prom 1 (Usfr1) Register (La, Lb Only); Uprom Programming Values And Locations - Intel 87C196CA Supplement To User’s Manual

8XC196L X SUPPLEMENT
USFR1 (read only)
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
— —
Bit Bit
Number Mnemonic
7:2 —
1:0 CLK1:0
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
2.5

INTERNAL 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
— —
Reserved.
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)
Write this value
CLK0 0001H
CLK1 0002H
Address:
Reset State:
— — CLK1
Function
To this location
0768H
0728H
1FF2H
XXH
0
CLK0