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USB Low-Full-High Speed Peripherals

HansonQuan
New Contributor

Hello,

I would like clarification on certain comments made in this post:

https://community.cypress.com/t5/USB-Low-Full-High-Speed/cy7c65215-jtag-pin-types-and-connections/m-...

#1: Are pullups/pulldowns REQUIRED on the JTAG pins, or just SUGGESTED? If required, please confirm which pins get pullups/pulldowns.

#2: @YatheeshD_36 makes the comment: "Once SCB 1 is configured as JTAG the other interface in CY7C65215 cannot be used." This is NOT my understanding. I thought the restriction was that SCB 0 and SCB 1 could not be used concurrently. Please clarify, as this will severely affect my design.

#3: (unrelated to the referenced post): In the datasheet, revision M (https://www.cypress.com/file/129956/download) table 17 shows that SCB1 Mode 7 (JTAG) has TDO as pin 5, and TDI as pin 6. In prior versions, these two were swapped. Please also confirm that revision M is correct.

Thank you.

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1 Solution
PranavaYN
Moderator
Moderator

Hi,

Sorry for the delayed response.

for #2, You can refer to [4] in Errata section which explicitly states "JTAG cannot be simultaneously used along with I2C/SPI/UART on SCB0. There will not be any functional impact while using JTAG and I2C/SPI/UART on SCB0 if both are not operated simultaneously."

For #3, latest revision  ( rev M)present in the Cypress website is accurate and can be followed.

Best regards,
Pranava

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3 Replies
PranavaYN
Moderator
Moderator

Hi,

#1 -> Pull up/down resistors were just a suggestion. JTAG can operate without any external components.

#2 -> Your understanding is correct. You just can't use them concurrently.

#3 -> Revision M of the datasheet is accurate. May I know which revision had those 2 values swapped?

 

Best regards,
Pranava

Best regards,
Pranava
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HansonQuan
New Contributor

Thank you for the quick reply.

For #2, I am deeply concerned about the statement found in revision M, page 6:

"Note: When JTAG is enabled, other interfaces in the CY7C65215/CY7C65215A device cannot be used."

This sounds like the other interfaces are permanently disabled, so I must really confirm which is true.

For #3, revision E, which is still referenced by many of your suppliers, has the TDI and TDO pins swapped.

Please reply at your earliest convenience.

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PranavaYN
Moderator
Moderator

Hi,

Sorry for the delayed response.

for #2, You can refer to [4] in Errata section which explicitly states "JTAG cannot be simultaneously used along with I2C/SPI/UART on SCB0. There will not be any functional impact while using JTAG and I2C/SPI/UART on SCB0 if both are not operated simultaneously."

For #3, latest revision  ( rev M)present in the Cypress website is accurate and can be followed.

Best regards,
Pranava

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