From 9e960c87af380973200ffa13eebb392291996d3c Mon Sep 17 00:00:00 2001 From: Thomas Date: Mon, 11 May 2020 08:51:50 +0200 Subject: [PATCH] Create README.md --- STM8S001J3RS485/README.md | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 STM8S001J3RS485/README.md diff --git a/STM8S001J3RS485/README.md b/STM8S001J3RS485/README.md new file mode 100644 index 0000000..d242679 --- /dev/null +++ b/STM8S001J3RS485/README.md @@ -0,0 +1,11 @@ +# STM8S001J3M3 based Micro MODBUS Node + +The STM8S001J3M3 is a low-pin-count µC in a SOIC-8 package. The chip is very similar to an STM8S903 and it has, like all other STM8S Low Density devices sufficient memory for supporting a Forth based MODBUS Server implementation. The "half-duplex" feature of the STM8S Low Density UART makes it possible to implement a normal RS485 interface with two GPIOs (shared RX-TX and direction controll). + +The [STM8S001 RS485 project](https://github.com/TG9541/stm8s001rs485) prototypes a very small STM8 eForth MODBUS node that, 1/4" (6.4mm) wide, fits in the same tube as a 8mm proximity switch: + +![STM8S001J3M3 MODBUS module](https://cdn.hackaday.io/images/3730111577482558707.png) + +Since `PD1/SWIM` is on the same pin as `PD5/RX-TX` a half-duplex a Forth console is available through `PC5`. The I2C bus on `PB4` and `PB5` is connected to an optional DS1621S temperature sensor and also accessible on pin headers. Two LEDs show direction and RX/TX bus activity: + +![STM8S001J3M3 MODBUS schematics](https://raw.githubusercontent.com/TG9541/stm8s001rs485/master/doc/STM8S001J3_RS485_sch.png)