CY7C68300B/CY7C68301B
CY7C68320/CY7C68321
8.0
Operating Modes
Read EEPROM
EEPROM
Found?
No
"No EEPROM Detected"
Mode
Yes
EEPROM
Signature
0x4D4D?
No
EEPROM
Signature
0x534B?
Yes
Set
EZ-USB AT2+
(CY7C68300A)
Pinout
Yes
Set
EZ-USB AT2LP
Pinout
No
ATA Enable
Pin HIGH?
No
Yes
No
ARESET#
LOW?
Normal Mass
Storage Mode
Yes
Board Manufacturing
Test Mode
Figure 8-1. Operational Mode Selection
8.1
Operational Mode Selection Flow
During the power-up sequence, the AT2LP checks the I
2
C port
for an EEPROM and checks to see if the ATA connector is
configured for Board Manufacturing Test Mode. AT2LP then
selects an operating mode as shown below.
• If an I
2
C EEPROM with a 0x4D4D signature is found, the
CY7C68300B/CY7C68301B uses the same pinout and EE-
PROM format as the CY7C68300A (EZ-USB AT2).
Document 38-08033 Rev. *D
• If the first two bytes of the EEPROM contain 0x534B the
AT2LP uses the values stored in the EEPROM to configure
the USB descriptors for normal operation.
• If no EEPROM is detected, the AT2LP uses a VID/PID of
0x00/0x00. This is not a valid mode of operation.
• If an invalid EEPROM signature is read, the AT2LP defaults
into Board Manufacturing Test Mode.
There is an additional method available to put the AT2LP into
Board Manufacturing Test Mode to allow reprogramming of
Page 15 of 36
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