Epson U675 - TM Color Dot-matrix Printer, Service Manual

Page: 232 / 325

Appendix D-44 Product Overview Rev.D
Confidential
CPU and Peripheral Logic Circuits
CPU
CPU Terminals and Functions
Table D-6 CPU specifications
Item Specification
External Data Bus Width 16 bits
Internal Data Bus Width 32 bits
External Clock
(root oscillation) 9.83 MHz
Bus Speed 19.66 MHz
Product Number TMP94C251F (Toshiba)
Internal RAM 256 bytes (used as stack area)
A/D Input Ports 7
Four slip sensors (TOF detector, BOF detector, ejection detector, validation
detector), and one each for MICR head reading, power source voltage
monitoring, impact head thermistor voltage
D/A Output Port 1
Carriage motor reference voltage
Table D-7 CPU terminals and functions
Port (Terminal) Pin Description Circuit Signal I/O I/O Definition
Name No. Name H L
DAREFH 1 VCC
 
DAREFL 2 GND
 
DAOUT0 3 For thermal PF, current setting THPF_DA OUT 5/256 0/256
DAOUT1 4 For impact CR, current setting CR_DA OUT 5/256 0/256
DVCC 5 VCC
PC0 6 Paper roll near end (common
for HB/U175) ROL_NE IN Paper
detected No paper
PC1 7 Paper end (roll paper) ROL_RE IN No paper Paper detected
PD0 8 Thermal PF_PHASE1 THPF_PH1 OUT
PD1 9 Thermal PF_PHASE2 THPF_PH2 OUT
PD2 10 Thermal PF_I01 THPF_I01 OUT
PD4 11 Thermal PF_I02 THPF_I02 OUT
PD5 12 Thermal PF_I11 THPF_I11 OUT
PD6 13 Thermal PF_I12 THPF_I12 OUT
DVSS 14 GND
PE0 15 DSW2-5 DSW2-5 IN OFF ON