Ver 2.4
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CY3650 USB Development System User’s Guide
4. Software Installation
For information on operation of the interactive PC debug environment, refer to the USB Development System
Software Guide.
For information on the CYASM assembly language programming and the assembler, refer to the CYASM Assem-
bler User’s Guide.
5. Operation
5.1. Differences between the chip and the development board
The development board is lacking some of the features that are present on the integrated circuit. Three important
differences are:
1. No programmable pull-up resistors on GPIO pins
2. No programmable DAC currents on GPIO pins
3. The development board is not bus powered and therefore it is not initialized when the USB connector is
first attached.
5.2. Firmware ROM vs. RAM operation
The user’s program code will be executed from either a ROM (U5) or program RAM, depending on the setting of
switch S3-1 (see Table 2). The U5 ROM is a Cypress CY7C261-45, an 8k x 8 UV-erasable EPROM. Only 4k of
the EPROM is currently addressable. The program RAM supports the same memory size as the EPROM.
To program or erase the EPROM, refer to the data sheets for the Cypress CY7C261-45. The part can be repeatedly
reprogrammed as user firmware is updated. Follow appropriate ESD precautions when handling the part. When
installing U5 in the development board, note the IC orientation guide, shown on the board and in Figure 4.
The following examples illustrate typical procedures for operating from either ROM or RAM.
Example 1: Program ROM Operation
1. Develop assembly code; program this into the U5 Cypress CY7C261-45 EPROM.
2. Remove power from the development board.
3. Install U5 into the development board.
4. Set switch S3-1 for program ROM operation (see Table 2)
5. Apply power to the board.
Table 2: Switch S3 Configuration
Position
Open (1)
Closed (0)
Function
1
Program RAM
Program ROM (U5)
User-code Source
2
Run on Reset
Halt on Reset
Operation at Reset
3
–
Default
Unused
4
–
Default
Unused
5
–
Default
Unused
6
–
Default
Unused
7
–
Default
Unused
8
–
Default
Unused
