Block Transfer Mode - Renesas H8S/2100 Series Hardware Manual

6-bit single-chip microcomputer

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Section 14 Serial Communication Interface (SCI)

For the direct convention type, logic levels 1 and 0 correspond to states Z and A, respectively, and

data is transferred with LSB-first as the start character, as shown in figure 14.23. Therefore, data

in the start character in the figure is H'3B. When using the direct convention type, write 0 to both

the SDIR and SINV bits in SCMR. Write 0 to the O/E bit in SMR in order to use even parity,

which is prescribed by the smart card standard.

Figure 14.24 Inverse Convention (SDIR = SINV = O/E = 1)

For the inverse convention type, logic levels 1 and 0 correspond to states A and Z, respectively

and data is transferred with MSB-first as the start character, as shown in figure 14.24. Therefore,

data in the start character in the figure is H'3F. When using the inverse convention type, write 1 to

both the SDIR and SINV bits in SCMR. The parity bit is logic level 0 to produce even parity,

which is prescribed by the smart card standard, and corresponds to state Z. Since the SINV bit of

this LSI only inverts data bits D7 to D0, write 1 to the O/E bit in SMR to invert the parity bit in

both transmission and reception.

Block Transfer Mode

Block transfer mode is different from normal smart card interface mode in the following respects.

• If a parity error is detected during reception, no error signal is output. Since the PER bit in

SSR is set by error detection, clear the bit before receiving the parity bit of the next frame.

• During transmission, at least 1 etu is secured as a guard time after the end of the parity bit

before the start of the next frame.

• Since the same data is not re-transmitted during transmission, the TEND flag in SSR is set

11.5 etu after transmission start.

• Although the ERS flag in block transfer mode displays the error signal status as in normal

smart card interface mode, the flag is always read as 0 because no error signal is transferred.

Rev. 1.00 May 09, 2008 Page 410 of 954

REJ09B0462-0100