USB-Serial Bridge Controller FAQs - KBA224054
Author: HirotakaT_91 Version: *E
Question: When the SSEL_IN input is "High" in Mode 4, what is the MISO_OUT output as listed in Table 14, Mode 4 (SPI Slave) in CY7C65211 datasheet (Rev *K)?
Answer: When the SSEL_IN input is HIGH, the slave is not enabled. At that time, the MISO_OUT, which is an OUTPUT pin, will be in the High-Z state.
Question: If GPIO0 to 7 of CY7C65213 are unused, is it OK leave them floating?
Answer: GPIOs can be left floating if configured as output pins. If the ports are configured as input pins, these ports must be connected to pull-up/pull-down resistors. Recommend resistance value is 10 kW.
Question: Can the Exposed Pad be connected to GND?
Answer: Yes. You can connect the Exposed Pad (EPAD) to GND directly. See the CYUSBS232/234/236 USB-Serial DVK schematic where EPAD is connected to GND directly.
Question: During power-on reset, what is the current consumption of CY7C65211/213/215?
Answer: The current consumption is lower than the suspend state current consumption (Typ. 5 µA) because the device is in the disable state during POR.
Question: What is the status of I/O pins during the reset sequence?
Answer: All I/O pins are tri-stated during reset.
Question: Can CY7C65211/213/215 enter suspend state with user intervention?
Answer: No. The user cannot set or program the device into suspend mode. The device enters suspend state after the device sees a consistent idle state on its USB bus lines. This behavior is USB Specification-compliant.
Question: What is the Cypress' recommendation to program USB-Serial Bridge products (such as CY7C65211/65213/65215) for mass-production?Answer: Cypress recommends that you use "USB Serial Configuration Utility" command-line program for programming. USB Serial Configuration Utility GUI is easy to program a firmware, but it is not efficient. For more information, see the thread in Cypress Developer Community: https://community.cypress.com/thread/30556
Question: Can Cypress program the .cyusb file that a customer prepared for their mass-production to customer' USB-Serial Bridge chip before shipment
Answer: Typically, no. It depends on the amount of mass-production. For more detail, contact Cypress FAE or Sales.
Question: Are USB-Serial Bridge products able to use .hex file instead of .cyusb file for programming a firmware?
Answer: No, they are not. These can use only .cyusb file for programming a firmware. It can be made by “USB Serial Configuration Utility” which supports only Windows OS.
Question: Does Cypress have a tool for converting .cyusb into .hex file?
Answer: No. Cypress does not offer a method for converting these file formats. For more information, contact Cypress FAE or Sales.
Question: What are the DC specifications of the UART pins (TX/RX/#CS/etc.) for CY7C65213?
Answer: DC specifications of the GPIO also apply to UART pins.
Question: What is the power on/off sequence of VCC and VCCIO for CY7C65213?
Answer: Ideally, there is no power up sequence of VCC and VCCIO. Very small delays in the order of nanoseconds (ns) do not matter. Powering up both the VCC and VCCIO together will work fine. It is also possible to have VCCIO present and connect VBUS later.
Question: Can I update the firmware for CYUSBS232 using I2C?
Answer: No, you cannot. CY7C65213 chip is implemented on CYUSBS232 Kit. The CY7C65213 chip is used only as a USB-UART Bridge Controller. To use the USB-I2C Bridge Controller chip, please use the CYUSBS234 Kit (CY7C65211 chip is implemented) or CYUSBS236 Kit (CY7C65215 chip is implemented).
Question: Is it possible to estimate the USB-UART conversion delay in CY7C65211/213/215?
Answer: Conversion will complete between 1 ms - 4 ms. 4 ms is the worst-case scenario.
It is difficult to accurately estimate the conversion delay because there are two main types of variables that are beyond the control of the USB-Serial device:
- Delay between the origin of data from a terminal application and the arrival of data at the USB-UART device.
- Flow control related UART Tx
Question: Does Cypress provide vendor class iOS driver for CY7C65211/213/215?
Answer: No. Cypress does not provide vendor class driver for iOS.
Question: Are CY7C65211 and CY7C65211A devices identical?
Answer: No, both are different parts. CY7C65211A has additional features compared to CY7C65211. See the CY7C65211 datasheet http://www.cypress.com/documentation/datasheets/cy7c65211-usb-serial-single-channel-uarti2cspi-bridg...
Question: Can I change the SPI frequency with a terminal console such as Tera Term?
Answer: Yes. The USB Serial Configuration Utility values always represent firmware defaults during the part initialization. Some of the parameters such as frequency and data width can be changed dynamically at run time from the host. Some parameters such as mode (SPI slave/master) are statically configured with the USB Serial Configuration Utility.
Question: Why does the CY7C65211 send short USB IN data packets during SPI transfer?
Answer: The SPI IN data overflow watermark will attempt to send as much data as possible to avoid data overflow. As a result, every incoming last 8 bytes of the USB IN data is affected. Therefore, it is possible to receive a few short packets at the end of an SPI transfer.
- CYUSBS232 USB-UART LP Reference Design Kit
- CYUSBS234 USB-Serial (Single Channel) Development Kit
- CYUSBS236 USB-Serial (Dual Channel) Development Kit
- USB-Serial Software Development Kit
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