HD64F2357F20V Datasheet, PDF (563/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

If a parity error occurs during reception and the PER is set to 1, the received data is still transferred to RDR, and therefore
this data can be read.
Mode Switching Operation: When switching from receive mode to transmit mode, first confirm that the receive
operation has been completed, then start from initialization, clearing RE bit to 0 and setting TE bit to 1. The RDRF flag or
the PER and ORER flags can be used to check that the receive operation has been completed.
When switching from transmit mode to receive mode, first confirm that the transmit operation has been completed, then
start from initialization, clearing TE bit to 0 and setting RE bit to 1. The TEND flag can be used to check that the transmit
operation has been completed.
Fixing Clock Output Level: When the GSM bit in SMR is set to 1, the clock output level can be fixed with bits CKE1
and CKE0 in SCR. At this time, the minimum clock pulse width can be made the specified width.
Figure 15-8 shows the timing for fixing the clock output level. In this example, GSM is set to 1, CKE1 is cleared to 0, and
the CKE0 bit is controlled.
Specified pulse width
Specified pulse width
SCK
SCR write
(CKE0 = 0)
SCR write
(CKE0 = 1)
Figure 15-8 Timing for Fixing Clock Output Level
Interrupt Operation: There are three interrupt sources in Smart Card interface mode: transmit data empty interrupt (TXI)
requests, transfer error interrupt (ERI) requests, and receive data full interrupt (RXI) requests. The transmit end interrupt
(TEI) request is not used in this mode.
When the TEND flag in SSR is set to 1, a TXI interrupt request is generated.
When the RDRF flag in SSR is set to 1, an RXI interrupt request is generated.
When any of flags ORER, PER, and ERS in SSR is set to 1, an ERI interrupt request is generated. The relationship
between the operating states and interrupt sources is shown in table 15-8.
Table 15-8 Smart Card Mode Operating States and Interrupt Sources
Operating State
Transmit Normal
Mode
operation
Error
Receive Normal
Mode
operation
Error
Flag
TEND
Enable Bit
TIE
Interrupt DMAC
Source Activation
TXI
Possible
DTC
Activation
Possible
ERS
RIE
RDRF
RIE
ERI
Not possible Not possible
RXI
Possible
Possible
PER, ORER RIE
ERI
Not possible Not possible
Data Transfer Operation by DMAC or DTC: In Smart Card mode, as with the normal SCI, transfer can be carried out
using the DMAC or DTC. In a transmit operation, the TDRE flag is also set to 1 at the same time as the TEND flag in
SSR, and a TXI interrupt is generated. If the TXI request is designated beforehand as a DMAC or DTC activation source,
the DMAC or DTC will be activated by the TXI request, and transfer of the transmit data will be carried out. The TDRE
Rev.6.00 Oct.28.2004 page 533 of 1016
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