SH7280 Datasheet, PDF (1481/1726 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine family

Section 26 Flash Memory
(2) Bit-Rate Matching State
In bit-rate matching, the boot program measures the low-level intervals in a signal carrying H'00
data that is transmitted by the host, and calculates the bit rate from this. The bit rate can be
changed by the new-bit-rate selection command. On completion of bit-rate matching, the boot
program goes to the inquiry and selection state. The sequence of processing in bit-rate matching is
shown in figure 26.22.
Host
Boot program
H'00 (max. 30 times)
H'00 (bit rate matching complete)
H'55
H'E6 (response)
H'FF (error)
Measures the
length of one bit
Figure 26.22 Sequence of Bit-Rate Matching
(3) Communications Protocol
Formats in the communications protocol between the host and boot program after completion of
the bit-rate matching are as follows.
1. One-character command or one-character response
A command or response consisting of a single character used for an inquiry or the ACK code
indicating normal completion.
2. n-character command or n-character response
A command or response that requires n bytes of data, which is used as a selection command or
response to an inquiry. The length of programming data is treated separately below.
3. Error response
Response to a command in case of an error: two bytes, consisting of the error response and
error code.
Rev. 1.00 Jun. 26, 2008 Page 1451 of 1692
REJ09B0393-0100