EYE ON NPI - NXP SC18IM704 UART to I²C-Bus Bridge #DigiKey @digikey @NXP
36This week's EYE ON NPI will woo you like a period romance show - no, we're not talking about Bridgerton, this is a different kind of Bridge! We're highlighting NXP's SC18IM704 UART to I²C-Bus Bridge (https://www.digikey.com/en/product-highlight/n/nxp-semi/sc18im704-uart-to-i2c-bus-bridge). This is a chip or module that will let you take an existing system with RS-232 or UART Serial and wedge in I2C support. Handy for desktop computer systems that just need to integrate a single sensor or control in userspace or embedded computers without extra GPIO: having user-space support for I2C, ADC, DAC or SPI is rare if you don't happen to have a BeBox (https://en.wikipedia.org/wiki/BeBox) but you can get almost any kind of device connected if you've got I2C!
These sorts of bridge devices could also be super useful during the chip shortage (https://en.wikipedia.org/wiki/2020%E2%80%93present_global_chip_shortage) - which we think will continue through until 2024 - where you have a design that has the right matching peripheral set, and then at the last minute, a part can't be sourced and you end up needing to re-spin the design. You may be able to get a similar spec part but...it doesn't have UART, only I2C, or SPI, or any mix-and-match combination of the three! For that reason, there's actually a couple different bridge chips that NXP makes (https://www.nxp.com/products/peripherals-and-logic/signal-chain/bridges:MC_50962)
The SC18IM704 (https://www.digikey.com/short/j242d1nm) has a single UART in and an I2C output, with 8 additional GPIO pins that can be handy for IRQ or busy pin reading, or for resetting pins or changing address selects. Commands are sent as bytes, and the user can initiate I2C start/stop, then read/write as well as setting GPIO direction, pull and value. Since NXP now owns Philips who wrote the I2C specification, (https://www.i2c-bus.org/specification/) you can be sure that this chip will work well with any I2C-standard sensor or expander you could find.
If you aren't integrating the chip, like say you have a computer board or other industrial device and you just want to get started fast, you can pick up the NXP SC18IM704-EVB eval board (https://www.digikey.com/en/products/detail/nxp-usa-inc./SC18IM704-EVB/15777144) which provides an RS-232 port and plug and play headers with 3V logic and 5V compliance.
Like many new product introductions lately, there were not many chips released in the initial stock and they're currently sold out! However, the NXP SC18IM704 UART to I²C-Bus Bridge (https://www.digikey.com/short/j242d1nm) is a stocking part on Digi-Key and a few thousand will be shipping in 2 months, so you can book an order today and have it send to you as soon as its available!