RX610 Group
26. ROM (Flash Memory for Code Storage)
R01UH0032EJ0120 Rev.1.20
Page 878 of 1006
Feb 20, 2013
commands, explicit execution of erasure is not necessary unless newly programmed data are to be erased without a
further reset.
Other than the programming and erasure commands, commands from the host for execution in this state include those for
sum checking of the user mat and user boot mat, blank checking (to confirm erasure), reading from memory, and
acquiring state information.
26.10.4
Automatic Adjustment of the Bit Rate
When the RX610 is booted up in boot mode, asynchronous transfer by the SCI is used to measure the periods at low level
of consecutive bytes with value 00h that are sent from the host. While the period at low level is being measured, set the
host’s SCI parameters to eight-bit data, one stop bit, no parity, and a transfer rate of 9,600 bps or 19,200 bps. The RX610
calculates the host's SCI bit rate from the measured periods at low level, adjusts its own bit rate accordingly, and then
sends a 00h byte to the host. If reception of the value 00h by the host is normal, the host responds by sending the value
55h to the RX610. If normal reception of 00h by the host is not possible, the RX610 is re-booted in boot mode, and then
repeats the process of automatically adjusting the bit rate. If reception of the value 55h by the RX610 is normal, it
responds by sending E6h to the host, and if normal reception of 55h by the RX610 is not possible, it responds by sending
FFh to the host.
Start
bit
D0
D1
D2
D3
D4
D5
D6
D7
Stop
bit
Measurement of low-level period for nine bits
(data is 00h)
High-level period for at
least one bit
Figure 26.27 Transfer Format Used by the SCI in Automatic Adjustment of the Bit Rate
Host
RX610
Measures 9-bit
period
00h (up to 30 times)
00h (on completion of automatic adjustment)
55h
E6h (for normal reception of 55h) or FFh (error)
Figure 26.28 Sequence of Transfer between the Host and RX610
Since the bit rate of the RX610's SCI module depends on the frequency of the peripheral clock, adjustment to match the
bit rate of the host will not be possible under some conditions. Accordingly, ensure that SCI transfer is under the
conditions given in table 26.12.
Summary of Contents for RX600 Series
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