Product
Yellow-Green 20x4 Character SPI LCD
Part Number: CFA634-YFH-KP
This intelligent character display module allows the choice between the legacy serial communication for backward compatibility and Crystalfontz's error-reducing packet communication style. Both of these communication styles provide powerful command sets for controlling the display. Do you need to control fans too? Check out the CFAFBSCAB which is compatible with this module using packet communication.
The 20x4 character display in its attractive stainless steel bezel displays characters that are 7.3 mm (0.29") tall, making it easily readable. And the range of color options lets you choose the perfect module for your application.
With each module capable of communicating via 6 interfaces, and the interfaces configurable by the end user, this module offers tons of flexibility. While these modules are all able to be configured for any interface (see the datasheet for details), this modules interface is configured for SPI.
Key Features:
- Attractive stainless steel bezel.
- Optional PC CDROM mounting bracket with overlay to fit two 5.25" wide bays is available.
- The CFA634 can use one of SIX interfaces on any modules in the family by changing the interface selection using a command setting or tactile button and making the appropriate jumper configurations.
- Adjustable contrast. The module's default contrast value will be acceptable for many applications. If necessary, you can adjust the contrast by using the control function.
- Extended voltage (9-15 volts for interfaces using DB9 connector) and 5 volts power inputs standard for the controller.
- Backlight is 5 volts only.
- Use the nonvolatile memory capability (EEPROM) to customize the "power-on" display settings.
Not sure which intelligent LCD module to choose? Compare all of our intelligent display modules.
Currently Shipping: HW Version 4, Firmware Version: 4
CFA - Crystalfontz (no 4th letter indicates value added)
634- Module Family Name
Y- Yellow-green LED backlight
F- FSTN, positive image, neutral glass
H- Transflective, 6:00 viewing direction
KP- SPI interface
Product Variations
Interfaces | Logic Level Serial InvertedSPILogic Level SerialI2CUSBRS232 |
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Colors | Yellow-Green on Black Yellow-Green LED BacklightWhite on Blue White LED BacklightBlack on Yellow-Green Yellow-Green LED BacklightDark on Light-Gray White LED Backlight |
|---|
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Part Change Notices
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Product Update #11349: CFA634YFH Variants are now available
Products Affected: CFA634-YFH-KS, CFA634-YFH-KU, CFA634-YFH-KC, CFA634-YFH-KL, CFA634-YFH-KP, CFA634-YFH-KN Date Issued: July 16, 2025 Summary: CFA634YFH Variants are now available Description: CFA634YFH variants have been released on our website with the changes noted in PCN#11149, #11204, and #11226. Orders can be placed directly from our website or by submitting a purchase order to sales@crystalfontz.com. Contact support@crystalfontz.com for any technical questions. - text_snippet
Part Change Notice #11226: Change to ENIG from Gold Plating
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Part Change Notice #11204: CFA634 Update to PCN11149
Products Affected: CFA634-TFH-KS, CFA634-TMI-KS, CFA634-YFH-KS, CFA634-YDI-KS, CFA634-TFH-KU, CFA634-TMI-KU, CFA634-YFH-KU, CFA634-YDI-KU, CFA634-YDI-KC, CFA634-TMI-KC, CFA634-YFH-KC, CFA634-TFH-KC, CFA634-YFH-KL, CFA634-TFH-KL, CFA634-TMI-KL, CFA634-YDI-KL, CFA634-TFH-KP, CFA634-YFH-KP, CFA634-TMI-KP, CFA634-YDI-KP, CFA634-TFH-KN, CFA634-YFH-KN, CFA634-TMI-KN, CFA634-YDI-KN Date Issued: June 19, 2023 Summary: CFA634 Update to PCN11149 Description: Update to PCN11149:
Electrical characteristics will be different including logic voltage. The inputs will be 5V tolerant but outputs from the CFA634 display modules will be 3.3V. For detailed changes, we will be releasing the updated datasheets on the relevant product pages. Contact support@crystalfontz.com if you would like to be notified when the updated datasheet is released.
Original notice:
The CFA634 family is having a hardware revision that utilizes a new processor and has other improvements that include: an independent voltage source so that the contrast is not affected by the input voltage, an interface select button, and will now support packet-based communication. The firmware has also been updated with additional features.
JPBL will be closed by default which will enable the backlight to be powered from USB.
Please refer to the datasheet for more information about the new hardware and firmware functions.Reason: Continuous improvement for this family of products. Availability: Contact Crystalfontz Support for up-to-date information by emailing support@crystalfontz.com.
Contact Crystalfontz Sales to order samples of the new revision by emailing sales@crystalfontz.com. - text_snippet
Part Change Notice #11149: New Hardware Revision
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Part Change Notice #10658: Deprecation of "Drive Bay Kit Configurator" / New part numbers for drive bay kits.
Products Affected: CFA631-RMF-KU1, CFA631-RMF-KU2, CFA631-RMF-KU, CFA633-YYB-KS, CFA633-TMC-KS, CFA633-RMC-KS, CFA633-YYB-KU, CFA633-TMC-KU, CFA633-RMC-KU, CFA635-YYE-KS, CFA635-TMF-KS, CFA635-TFE-KS, CFA635-TMF-KL, CFA635-TFE-KL, CFA631-TMF-KU, CFA635-TFE-KU, CFA635-YYE-KL, CFA635-TMF-KU, CFA635-YYE-KU, DS635-AL, DS635-BG, DS635-BK, DS635-AK, CFA533-YYH-KS, CFA533-YYH-KU, CFA533-TMI-KS, CFA533-TMI-KU, CFA533-YYH-KL, CFA533-TMI-KL, CFA533-YYH-KC, CFA533-TMI-KC, CFA533-YYH-KI, CFA633-YYH-KS, CFA633-TMI-KS, CFA633-YYH-KU, CFA633-TMI-KU, CFA632-YFH-KS, CFA632-YDI-KS, CFA632-YFH-KU, CFA632-YDI-KU, CFA634-TFH-KS, CFA634-TMI-KS, CFA634-YFH-KS, CFA634-YDI-KS, CFA634-TFH-KU, CFA634-TMI-KU, CFA634-YFH-KU, CFA634-YDI-KU, CFA633-RDI-KU, CFA633-RDI-KS, CFA533-TFH-KU, CFA533-TFH-KS, CFA633-TFH-KU, CFA633-TFH-KS, CFA533-TFH-KL, CFA533-TFH-KC, CFA735-TFK-KR, CFA735-TFK-KT, CFA735-TML-KR, CFA735-TML-KT, CFA735-YYK-KR, CFA735-YYK-KT, CFA631-RMF-KU32, CFA631-RMF-KU128, CFA631-RMF-KU160, CFA633-RDI-KU16, CFA631-RMF-KU33, CFA631-RMF-KU129, CFA631-RMF-KU161, CFA631-RMF-KU-162, CFA632-YDI-KL, CFA632-YDI-KN, CFA632-YDI-KC, CFA632-YDI-KP, CFA632-YFH-KL, CFA632-YFH-KN, CFA632-YFH-KC, CFA632-YFH-KP, CFA634-YDI-KC, CFA634-TMI-KC, CFA634-YFH-KC, CFA634-TFH-KC, CFA634-YFH-KL, CFA634-TFH-KL, CFA634-TMI-KL, CFA634-YDI-KL, CFA634-TFH-KP, CFA634-YFH-KP, CFA634-TMI-KP, CFA634-YDI-KP, CFA634-TFH-KN, CFA634-YFH-KN, CFA634-TMI-KN, CFA634-YDI-KN, CFA631P-TMF-KU Date Issued: July 1, 2015 Summary: Deprecation of "Drive Bay Kit Configurator" / New part numbers for drive bay kits. Description: Starting August 1, 2015 the "Drive Bay Kit Configurator" located at https://www.crystalfontz.com/products/select_kit.html will no longer be functional for ordering one of our Serial or USB displays (CFA533, CFA631, CFA632, CFA633, CFA634, CFA635, and CFA735) in a bracket or SLED. This functionality is being moved to the Customize and Add to Cart process when checking out. This will allow for further customization by our customers to better fit their needs.
This change will eliminate the current "kits", but will add options not previously available such as pre-configured ATX functionality, and ALL the currently available interfaces will be orderable in a drive bay bracket or SLED.
The new part numbers will have the bracket / SLED and overlay type as a PREFIX to the configured part number. The choice for bracket / SLED to a display order will be via the cart options. Our CFA835 displays were introduced with these configuration options.
To see how the new options will look, and what the new part numbers will look like, please see one of our CFA835 parts:
https://www.crystalfontz.com/cart/addtocart.php?product_id=2277&qty=1
NOTE: The SLED is only available for the CFA635, CFA735, and CFA835 products.
Reason: As part of our continuous improvement process, we are integrating the ordering of displays in drive bay and SLED kits as part of the display ordering process. Impact: Drive bay kits in their current configuration will no longer be available. Recommendation: Place orders prior to 2015-08-01 for upcoming production needs via our website or by contacting our logistics department via email: sales@crystalfontz.com, or by calling 1-888-206-9720 (International call +1-509-892-1200).
After the 2015-08-01, please contact our engineering department via support@crystalfontz.com to assist you with ordering your bracket / SLED kits.
Availability: Starting 2015-08-01, the bracket and SLED options for our serial and USB display will be part of the ordering process for the displays Price Change: Pricing bracket / SLED configurations will reflect manufacturing costs. - text_snippet
Part Change Notice #10650: CFA634 Firmware update
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Part Change Notice #10580: Reverted the SPI functionality to Crystalfontz CFA634 legacy implementation
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Product Update #10531: (New Product) CFA634YFHKP
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