CY3684 Cypress Semiconductor Corp, CY3684 Datasheet - Page 12

• Manufacturer Part Number: CY3684
• Description: KIT DEVELOPMENT EZ-USB FX2LP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB FXr
• Type: MCUr

Specifications of CY3684

• Contents: 2 Boards, Cables, CD
• Silicon Manufacturer: Cypress
• Application Sub Type: USB
• Kit Application Type: Interface
• Silicon Core Number: CY7C68013A-128AXC
• Features: FX2LP Development Kit
• Silicon Family Name: EZ-USB FX2LP
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: CY7C68013A-128AC, CY7C64713-128AC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1677; CY3684; Q2204408

“Small” EEPROMS are typically used to supply custom VID and PID information, allowing the EZ-
USB to enumerate with a driver associated with your EZ-USB design.
“Large” EEPROMS are typically used to boot-load code into internal EZ-USB RAM, and then start
up the 8051 to execute this internal code which performs the enumeration.
The EZ-USB loader determines the EEPROM size by first initiating an I
1010000 (1010 is the EEPROM class address, and 000 is the sub-address). If the device supplies
an I
the internal EEPROM address pointer to zero.
If the above transfer does not return an ACK pulse, the EZ-USB loader initiates a second I
transfer, this time to address 10100001 (1010=EEPROM, sub-address 001). If an ACK is returned
by the I
EEPROM address pointer to 0.
If neither transfer returns an ACK pulse, the EZ-USB loader boots in ‘generic’ mode (explained
below).
Tree EZ-USB startup sequences, and the associated settings for SW1 and SW2, are shown
below.
1. Generic’:
2.
Page -8
2
When no EEPROM is connected to SCL and SDA, the EZ-USB chip enumerates using its
internal, “hard-wired” VID and PID values. This mode can be selected without requiring the
removal of any socketed EEPROMS by switching SW2 to the ‘off’ (down) position. This elec-
trically disconnects any EEPROMS that occupy the EEPROM sockets U5 and U6. The “OFF”
mode is handy for starting up EZ-USB in a manner (using internal VID/PID) that binds the
development system board to the Cypress debug tools such as the Control Panel and Keil
debug tools. Once running, SW2 can be switched to the ON position to allow 8051 access, for
example to re-program the EEPROM.
A “C0” load provides EZ-USB with external VID, PID and DID values, allowing it to enumerate
with the EEPROM-supplied VID/PID/DID.
At power-on, if the EZ-USB chip detects an EEPROM with the hex value ‘C0’ as its first byte,
it continues to load seven additional EEPROM bytes, which correspond to the USB Vendor ID
(VID), Product ID (PID), Device ID (DID), and an EZ-USB configuration byte. Then when EZ-
USB enumerates, it uses these EEPROM values rather than the hard-wired internal values.
Since only eight bytes of data are required, a ‘small’ EEPROM is generally used for this mode,
for example the 16-byte 24LC00.
C acknowledge pulse, the EZ-USB loader writes a single EEPROM address byte to initialize
‘C0 Load’:
2
C-device, the EZ-USB loader writes two EEPROM address bytes to initialize the internal
SW2=OFF, SW1=either position
SW2=ON, SW1=SMALL
EEPROM Type
Table 2. Typical EZ-USB external EEPROMS
“Small”
“Large”
128x8
256x8
Size
8Kx8
16x8
EZ-USB Development Kit Manual - Getting Started Rev 1.0
A2A1A0
000
000
000
001
Typical P/N
24LC64/5
24LC00
24LC01
24LC02
2
C transfer to address
2
C