I am trying to build up an expansion board for my project. Your reference design is using the IP4856CX25/CZ chip. It seems that there is no inventory on this chip anywhere. See https://octopart.com/ip4856cx25/cz-nxp+semiconductors-34971082 https://octopart.com/ip4856cx25/cz-nxp+semiconductors-34971082 .
Do you have an alternate chip design that would be compatible with the current OS's?
In my search for alternative to IP4856CX25, which btw has a 24 week lead time (available 10/17/17), the alternative chips are:
1. NXP NVT4857UKZ - Nothing available.
2. http://www.ti.com/lit/ds/symlink/txs0206.pdf TI TXS0206 - Quantity available on digikey
Going with http://www.ti.com/lit/ds/symlink/txs0206.pdf TXS0206 - Can you help me mapping the connections from the Joule to the Chip. Here is a snap shot of the schematic from TI datasheet. I am trying to map the expansion board connections to this chip but having problems with pin functionality. I gave it a shot with text in red that maps to the expansion board schematic. But I am very confused on DIR_0, DIR_1_3, DIR_CMD, SEL pins.
Appreciate any help someone can offer.
Thanks for contacting us.
Unfortunately, the custom boards are out of the scope of this technical support team. Nevertheless, the recommendation that I can give you is to check the datasheet of the IP4856CX25 ( http://assets.nexperia.com/documents/data-sheet/IP4856CX25_C.pdf) to know exactly the function of each pin, and compare them with your chip's pins.
It looks like that you have to connect the pin SDCARD_CMD to the CMDA pin of your chip. And about the pins that you are confused, DIR_0, DIR_1_3, DIR_CMD, it seems that they are used to determine if a command and data signals are transferred from the memory card to the host (card read mode) or from the host to the memory card (card write mode).
I hope you find this information helpful.