Application Circuits
Host Controller with an HT1647 Display System
HT1647
M CU
C lo c k O u t
E x te r n a l C lo c k 1 ( 3 2 k H z )
E x te r n a l C lo c k 2 ( 3 2 k H z )
O n - c h ip O S C
C ry s ta l
32768H z
CS
*
RD
VDD
WR
D B 0~D B 3
H T1647
V LC D
*R
BZ
IR Q
O SCI
BZ
O S C O C O M 0 ~ C O M 15 S E G 0~S E G 63
* 1 /5 B ia s ( o r 1 /4 B ia s ) , 1 /1 6 D u ty
LC D P anel
*V R
P ie z o
*Note: The connection of IRQ and RD pin can be selected depending on the MCU.
The voltage applied to VLCD pin must be lower than VDD.
Adjust VR to fit LCD display, at VDD=5V, VLCD=4V, VR=15kW ± 20%.
It is recommended to select 1/5 bias to fit TN-type, STN-type LCDs and select 1/4 bias to fit ECB-type LCDs.
Adjust R (external pull high resistance) to fit user¢s time base clock.
Instruction Set Summary
Name
Command Code
D/C
Function
Def.
READ
A8110-A7A6A5A4A3A2A1A0D3D2D1D0 D Read data from the RAM
WRITE
A8101-A7A6A5A4A3A2A1A0D3D2D1D0 D Write data to the RAM
READ-MODIFY-
WRITE
A8101-A7A6A5A4A3A2A1A0D3D2D1D0
D Read and Write data to the RAM
SYS DIS
X100-0000-0000-XXXX
C
Turn Off both
generator
system
oscillator
and
LCD
bias
Yes
SYS EN
X100-0000-0001-XXXX
C Turn On system oscillator
LCD OFF
X100-0000-0010-XXXX
C Turn Off LCD display
Yes
LCD ON
X100-0000-0011-XXXX
C Turn On LCD display
TIMER DIS
X100-0000-0100-XXXX
C Disable time base output
Yes
WDT DIS
X100-0000-0101-XXXX
C Disable WDT time-out flag output
Yes
TIMER EN
X100-0000-0110-XXXX
C Enable time base output
WDT EN
X100-0000-0111-XXXX
C Enable WDT time-out flag output
TONE OFF
X100-0000-1000-XXXX
C Turn Off tone outputs
Yes
CLR TIMER
X100-0000-1101-XXXX
C Clear the contents of the time base generator
CLR WDT
X100-0000-1111-XXXX
C Clear the contents of the WDT stage
TONE 4K
X100-0001-0000-XXXX
C
Turn on tone output, tone frequency output:
4kHz
TONE 2K
X100-0001-0001-XXXX
C
Turn on tone output, tone frequency output:
2kHz
Rev. 1.30
14
November 10, 2005