Datasheet

Functional description ST7538Q
34/44
Function Value Selection Note Default
Bit 20
Active only if Extended
Control Register is
enable (Bit 21=”1”)
20
Header
Length
8 bits
16 bits
0
1
16 bits
Bit 21
Extended Register
enables Functions on
Bit 17, 18,19 and 20
21
Extended
Register
Disable (24 bits)
Enabled (48 bits)
0
1
Disabled
(24 bits)
Bit 22
22
Sensitivity
Mode
Normal
Sensitivity
High Sensitivity
0
1
Normal
Bit 23
23 Input Filter
Disabled
Enabled
0
1
Disabled
24 to
39
Frame
Header
from 0000h to
FFFFh
One 16 bits Header or
two 8 bits Headers
(MSB first) depending
on Bit 17
9B58h
40 to
47
Frame
Length
from 01h to FFh
Number of 16 bits
words expected
08h
1. The Detection method bit meaning differs depending on UART/SPI pin value. In this table is listed the SPI
mode (UART/SPI=”0”). For Detection method bit meaning in UART mode (UART/SPI=”1”) please see
Table 12.
Table 11. Control register functions (continued)