APPENDIX D BOOT
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
AP-D-7
START
Switches #CE10 pin to P53 input
Initializes TTBR (0x20000000)
Jumps to address 0x100
Initializes and starts T16A5 Ch.0
Counts low/high pulses
with T16A5 Ch.0
Calculates the baud rate from T16A5
Ch.0 count value
Determines the baud rate
and stops T16A5 Ch.0
Configures the port functions
0x80
×
4 bytes received
Start/stop bit
detected
No
No
Yes
Yes
P53 (#CE10)
1
To SPI-EEPROM
boot sequence
0
Uploads the chip ID
Downloads 512-byte executable code
Uploads 512-byte executable code
(for verification)
Initializes FSIO Ch.1
4.2.1 PC RS232C Boot Flowchart
Figure D.
(1) When the BOOT pin is set to 1 and the P53 (#CE10) pin is set to 0 at power-on or reset, the PC RS232C boot
sequence is executed.
(2) The boot sequence configures the port and the T16A5 Ch.0.
(3) Waits for the P00 (SIN1) input pulled-down to 0 (start bit). When a start bit is input, the boot sequence starts
T16A5 Ch.0 to measure the low level width.
(4) After 4 bytes of 0x80 sent from the PC have been input, the baud rate is calculated from T16A5 Ch.0 count
value, and FSIO Ch.1 is enabled with the calculated baud rate.
(5) The S1C33L26 uploads a 4-byte chip ID code to the PC.
The PC sends 512 bytes of executable codes to the S1C33L26 after the chip ID is verified.