SDI Technologies SDIO Card - Manual (Page 21)

©Copyright 2002-2006 SD Card Association
SDIO Card Bluetooth Type-A Simplified Specification Version 1.00
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Figure 9 describes the Type-A Transport packet Read operation from the Card to the Host in Byte Basis
transfer mode. When the Type-A Transport in the Host receives an interrupt via the Packet Read Ready
signal, it starts to read the Type-A Transport packet from the Card. This interrupt signal shall be issued
for receipt of Type-A Transport packets instead of receipt of SDIO data packets. The Type-A Transport
header is read first, and it is used to determine the length of the Type-A Transport packet. The Type-A
Transport in the Host then repeatedly reads each SDIO data packet using Byte Basis transfer mode
until the total length of the received SDIO data packets reaches the Type-A Transport packet length. It
then sets the PCRRT to "0" to indicate the success of packet read operation to the Type-A Transport in
the Card and assembles all SDIO data packets into one Type-A Transport packet. Finally it removes the
Type-A Transport packet header and informs the Type-A Host Control Interface of arrival of data packet.
In Figure 9, maximum transfer size is used in each SDIO data packets. However, smaller byte counts
may also be used.
When a CRC error occurs in the SDIO transmission, the Type-A Transport in the Host recognizes it
through the transmission result. It sets the PCRRT field to "1" in order to prepare for a re-read, and the
Type-A Transport in the Card issues an interrupt to the Host. When the interrupt is cleared, it shall try to
re-read the whole Type-A Transport data packet, including the erroneous SDIO data packet, until the
erroneous packet is received successfully or a number of retries designated by the Host are reached. If
the packet is not received successfully, the Type-A Transport sends a fatal error to the Host application.
The Host application should reset the Type-A Transport to resume Bluetooth communication.
Figure 9 – Type-A Transport Packet Read Operation from the Card to the Host in Byte
Basis Transfer Mode
Length (3 Bytes) Service ID (1 Byte)
Data (4 Bytes)
SDIO
Protocol
Multiplexing
Adaptation
Type-A Transport
SDIO Data (4 Bytes) SDIO Data (B Bytes) SDIO Data (B Bytes)
SDIO Data
((L – 4) mod B)
Byte Basis mode Byte Basis mode Byte Basis mode Byte Basis mode
When CRC error occurs in transmission, the Type-A Transport packet is re-read
Interface data (L –4) Bytes
Data (B Bytes) Data (B Bytes) Data ((L – 4) mod B)