
FlashMedia Interface
MOTOROLA
IDE and FlashMedia Interface
13-13
This is also true if CRC insertion is involved. If a 4096 bit packet + 16 bit CRC need to be transmitted
to the FlashMedia, 129 long-word transfers are needed. The first long-word will contain packet bits
4095:4080, MSB aligned. The last longword will contain packet bits 15:0 padded with 16 zeros or
ones. The padded value will be replaced with the CRC by the transmit interface. (if the interface is
programmed to do so.)
During and after transmission of a command, the processor can monitor the Interface Shift Register status
by looking at some status signals.
SHIFT_BUSY This signal is high while the data transmission is in progress.
INT_LEVEL During interrupt commands, a high on this signal indicates an interrupt event coming
from the FlashMedia.
CRC_IS_0 After a read transmission is completed, this signal indicates if the packet CRC was 0 or
not.
BITCOUNTER. This counter indicates the number of bits still to be exchange with the FlashMedia
card.
13.4.2.1
FlashMedia Command Registers in MemoryStick Mode
13.4.2.2
FlashMedia Command Register 1 in Secure Digital Mode
Table 13-10 FLASHMEDIA COMMAND REGISTERS (MemoryStick Mode)
FLASHMEDIACMD1
FLASHMEDIACMD2
BITS
FIELD NAME
RW
MEANING
RES
NOTES
15:0
BITCOUNTER
RW
Write to this field the number of bits to be
exchanged with the flash card.
Read value is the number of bits remaining.
0
19:16
CMDCODE
0001: read data (MemoryStick)
0010: write data (MemoryStick)
1000: wait for INT (MemoryStick)
0
20
NEXT BS
next value to output on BS pin (MemoryStick)
0
21
SENDCRC
0: No CRC inserted
1: packet bits 0-15 will be replaced with CRC
0
Table 13-11 FLASHMEDIA COMMAND REGISTER 1 (Secure Digital Mode)
FLASHMEDIACMD1
BITS
FIELD NAME
RW
MEANING
RES
NOTES
15:0
BITCOUNTER
RW
Write to this field the number of bits to
be exchanged with the flash card.
Read value is the number of bits
remaining.
0
19:16
CMDCODE
0
20
NEXT BS
next value to output on BS pin
(MemoryStick)
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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