Epson E0C6001 Technical Manual page 24

Table 4.1.1(d) I/O memory map
Register
Address
D3 D2
XBZR 0
R/W R
0FDH
* 1 Initial value following initial reset
* 2 Not set in the circuit
* 3 Undefined
* 4 Reset (0) immediately after being read
* 5 Constantly 0 when being read
* 6 Refer to main manual
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Memory Map)
D1 D0 Name SR
XFOUT1 XFOUT0 XBZR
*5
0
R/W
XFOUT1
XFOUT0
*1 1 0
0 2 kHz 4 kHz
Buzzer frequency control
High Low
0 FOUT frequency control:
XFOUT1(0), XFOUT0(0) -> F1
XFOUT1(0), XFOUT0(1) -> F2
XFOUT1(1), XFOUT0(0) -> F3
0 High Low
XFOUT1(1), XFOUT0(1) -> F4
Comment
I-17