User guide
CY3687 MoBL-USB FX2LP18 Development Kit User Guide, Doc. # 001-68582 Rev. *B 19
Development Board
3.4 EEPROM Select and Enable Switches SW1 and SW2
SW1 selects between two socketed EEPROMs, one strapped to address 000 (U8), and the other
strapped to address 001(U7).
SW2 enables or disables the EEPROM selected by SW1. When the SW1 EEPROMs are disabled,
the ‘Safe’ EEPROM is enabled.
The MoBL-USB chip has various start-up modes, which depend on the existence of an EEPROM
connected to its SCL and SDA lines. Switches SW1 and SW2 select among three EEPROMs on the
board. Each of these EEPROMs has a specific purpose:
■ U5 -- SAFE -- Used to select the default VID/PID for the board. Do not overwrite this EEPROM.
■ U7 -- Large -- Used for firmware download. User programmable.
■ U8 -- Small -- Used for VID/PID programming only. Used for reNumeration or default configura-
tion. The VID/PID allows the operating system to identify your device. You must have your own
VID assigned by the USB I/F. The ‘Using Cypress’ VID is not permitted.
On reset, the MoBL-USB I2C controller loads the image from one of these three EEPROMs. As this
process completes, the 8051 firmware can use the I
2
C controller to access the EEPROMs or both
devices on the I
2
C bus. The MoBL-USB bootloader accommodates two EEPROM types, in ‘Small’
and ‘Large’ versions shown in Table 3-2.
JP9
Current measurement
point or alter-nate
power input for 2.5V
supply
IN (1-2)
This jumper may be removed and replaced with ammeter
probes in series to measure current for this supply. This point
may be used to provide an external source for the 2.5 V supply.
JP10
Voltage selection for
VCCIO
1.8V (5-6) Selects the input voltage for VCCIO.
JP11
Current measurement
point or alter-nate
power input for 1.8V
supply
IN (1-2)
This jumper may be removed and replaced with ammeter
probes in series to measure current for this supply. This point
may be used to provide an external source for the 1.8 V supply.
JP12 WP for debug FX2LP IN (1-2)
When this jumper is in place, the debug firmware in the 100-pin
FX2LP is protected from accidental writes. Removing this
jumper allows the debug firmware to be overwritten.
Table 3-2. Typical MoBL-USB external EEPROMS
EEPROM Type Size A2A1A0 Typical P/N (2.5-3.3v) Typical P/N (1.8v)
‘Small’ 128x8 000 24LC01 24AA01
256x8 000 24LC02 24AA02
‘Large’ 16Kx8 001 24LC128 24AA128
Table 3-1. Jumper Settings
Jumper Function Default Notes