ST92195C STMicroelectronics, ST92195C Datasheet - Page 162

• Manufacturer Part Number: ST92195C
• Description: 48-96 Kbyte Rom Hcmos Mcu With On-screen Display And Teletext Data Slicer
• Manufacturer: STMicroelectronics

TELETEXT SLICER AND ACQUISITION UNIT (Cont’d)
Hamming 8/4 correction:
HDE[7:0]: on writing, these 8 bits are the data to
be Hamming 8/4 checked, where P are Hamming
bits D are Data bits.
HDE[23:8]: don't care.
ACQHD2R
ACQHD1R
ACQHD0R
D4
7
X
7
X
7
X
X
P
D3
X
X
X
X
P
D2
X
X
X
X
P
ST92195C/D - TELETEXT SLICER AND ACQUISITION UNIT
D1
X
X
0
X
0
X
0
P
On reading, the bits are redefined as follows:
ACQHD2R
ACQHD1R
ACQHD0R
Bits 23:5 = Don't care
Bit 4 = ERR: Hamming Error.
This bit is set by hardware and cleared by soft-
ware.
0: The 24-bit word is correctly Hamming decoded
1: The result of the Hamming decoding is wrong
Note: The D[4:1] bits are cleared by hardware
when ERR=1.
Bits 3:0 = D4-D1: Data
23
15
(no error or a recoverable error).
(unrecoverable error).
0
0
7
0
0
0
0
0
0
0
ERR
0
0
D4
0
0
D3
0
0
D2
0
0
162/249
16
D1
8
0
0
0