SNBC BTP-2002NP Service Manual page 27

Confidential
The CPU controls the printer according to the printer control program written in FLASH (U151). FLASH is
1MB/2MB depending on modules. SDRAM (U152) is 2MB.
2. Thermal Head Drive Circuit
The print head of the BTP-2002NP printer is a thermal type print head with 640 dots per line. All print head
control is performed via a gate array. A driver is built into the print head. CPU sends the print data by signal
TPHDAT, which is synchronized with the TPHCLK signal, to the driver sets the print/non-print status of
each dot. Data is latched by signal LATCH. Print time control is performed by ST1 and ST2.
CPU (U101) controls the power of the print head (on or off) by the signal DPEN-VTPH, which is connected
to the CPU pin (PIN58).
CPU can detect whether or not the temperature of the print head is too high by the temperature signal THM,
which is connected to the CPU (U101) pin (PIN 75).
The signal definition is below:
The control sequence diagram is below:
VH: voltage of the print head
ts: time of the dot heating
tl: time of printing one dot line
Pin Signal name
1 VH
2 VH
3 VH
4 GND
5 GND
6 GND
7 VCC
8 THM
9 /ST1
10 /ST1
11 /ST2
12 /ST2
13 TPH _CLK
14 /LATCH
15 TPH_DAT
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BTP-2002NP Service Manual
Function
24V
24V
24V
Ground
Ground
Ground
5V
Status
Strobe
Strobe
Strobe
Strobe
Clock
Latch
Data