h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 557

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

In a receive operation, an RXI interrupt request is generated when the RDRF flag in SSR is set to
1. If the RXI request is designated beforehand as a DTC activation source, the DTC will be
activated by the RXI request, and transfer of the receive data will be carried out. The RDRF flag is
cleared to 0 automatically when data transfer is performed by the DTC. If an error occurs, an error
flag is set but the RDRF flag is not. Consequently, the DTC is not activated, but instead, an ERI
interrupt request is sent to the CPU. Therefore, the error flag should be cleared.
Note: For block transfer mode, see section 13.4, SCI Interrupts.
14.3.7
Switching the Mode: When switching between smart card interface mode and software standby
mode, the following switching procedure should be followed in order to maintain the clock duty.
• When changing from smart card interface mode to software standby mode
[1] Set the data register (DR) and data direction register (DDR) corresponding to the SCK pin to
[2] Write 0 to the TE bit and RE bit in the serial control register (SCR) to halt transmit/receive
[3] Write 0 to the CKE0 bit in SCR to halt the clock.
[4] Wait for one serial clock period.
[5] Make the transition to the software standby state.
• When returning to smart card interface mode from software standby mode
[6] Exit the software standby state.
[7] Write 1 to the CKE0 bit in SCR and output the clock. Signal generation is started with the
the value for the fixed output state in software standby mode.
operation. At the same time, set the CKE1 bit to the value for the fixed output state in
software standby mode.
During this interval, clock output is fixed at the specified level, with the duty preserved.
normal duty.
Operation in GSM Mode
[1] [2] [3]
Normal operation
Figure 14.9 Clock Halt and Restart Procedure
[4] [5]
Software
standby
[6] [7]
Rev. 5.00 Sep 22, 2005 page 531 of 1136
Normal operation
Section 14 Smart Card Interface
REJ09B0257-0500