BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 111

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

BS85B12-3/BS85C20-3
Touch Key Flash MCU with LCD/LED Driver
Touch Key Function
Rev. 1.00
Touch Key Structure
Touch Key Register Definition
Each device provides multiple touch key functions. The touch key function is fully integrated and
requires no external components, allowing touch key functions to be implemented by the simple
manipulation of internal registers.
The touch keys are pin shared with the PC and PD logic I/O pins, as well as having dedicated pins. For
the pin shared touch keys, the touch key function is chosen using register bits. Keys are organised into
groups of four, with each group known as a module and having a module number, M0 to M4. Each
module contains its own control logic circuits and register set. Examination of the register names will
reveal the module number it is referring to.
Each touch key module, which contains four touch key functions, has its own suite of registers. The
following table shows the register set for each touch key module. The Mn within the register name
refers to the Touch Key module number and has a range of M0 to M4.
TKMn16DH
TKMn16DL
TKMnC0
TKMnC1
TKMnC2
TKMnC3
BS85B12-3
BS85C20-3
Name
Device
16-bit C/F counter high byte
16-bit C/F counter low byte
Control Register 0
Key Select
Control Register 1
Internal reference.
Touch pad reference.
Control Register 2
Counter on-off and clear control/reference clock control/TKST start bit
Control Register 3
Counter overflow bits
Keys - n
Touch Key Module/Pin Reference Table
12
20
Register Listing
Touch Key
Module
M0
M1
M2
M0
M1
M2
M3
M4
105
Usage
Touch Key
K13~K16
K17~K20
K9~K12
K9~K12
K1~K4
K5~K8
K1~K4
K5~K8
Shared I/O Pin
Dedicated Pins
Dedicated Pins
PC0~PC3
PC4~PC7
PC0~PC3
PC4~PC7
PD0~PD3
PD4~PD7
February 1, 2011