Regarding the KNX TP, I tested the STKNX evaluation board and my board which have ST-KNX chip then have below questions:
Q1, The testing connection is
UART TX => KNX_TX (STKNX EV1) => KNX_TP line => KNX_RX(STKNX chip board 2) => UART RX
CH1: KNX_TX CH2: KNX_TP_line Send out character 0xA5 @9600,8N2 | CH1: KNX_RX CH2: KNX_TP_line Received: 0xE9, 0x0E, 0x00 @9600,8N2 |
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- The received data is not same as send out data but the KNX_TP line waveform are same(both side CH2 are the same).
- You could see the KNX_TX waveform that idle state is at HIGH, the KNX_RX waveform that idle state is at LOW
- Although the waveform of the data are same, however, due to the KNX_RX idle state is LOW such that the receive side start bit are missing, also there are additional data appended at the end.
- My question is
- Q1-1 According to the provided waveform, do the ST-KNX chip working properly?
- Q1-2 Why the start bit are missing and there are additional data at the end?
Q2 Are the KNX_TX and KNX_RX using the UART to communicate?
Or using SPI?
or could just use the GPIO?
Q3: According to the STKNX evaluation board,
The KNX_TX and KNX_RX pin are connecting to PA6 and PA7 which the pin definition of STM32F103RB as below:
Since I don’t have the driver code, what feature(s) is(are) need to use for TAPKO KAIstack?
Assume that there are no AND gate at the PA7.
e.g. Do the TAPKO driver need the TIM3_CH1&2 function for the KNX TP?
