ELS61-E-R2 ASC0 -DSR0 is shared with the SPI_CLK line of the SPI interface | Telit Cinterion IoT Developer Community
March 19, 2019 - 10:07am, 2184 views
I'm a little bit confuse, I'm reading the hardware interface description of ELS61-E-R2 and I can see that DSR0 in ASC is shared with the SPI_CLK.
I would like to use TXD0 and RXD0 from ASC0 but I also would like to use the SPI. Do you know if is it possible to use both at the same time?
THis is the note which is confusing me:
Note: The ASC0 modem control lines DTR0, DCD0, DSR0 and RING0 are originally available
as GPIO lines. If configured as ASC0 lines, these GPIO lines are assigned as follows:
GPIO1 --> DTR0, GPIO2 --> DCD0, GPIO3 --> DSR0 and GPIO24 --> RING0. Also, DSR0 is
shared with the SPI_CLK line of the SPI interface and may be configured as such. Configuration
is done by AT command
Thanks in advance.
Some of the lines are shared between two different interfaces. You can configure this with AT^SCFG command. Module restart is needed in most cases for the configuration change to take effect. So the single common line may be used by the one interface only. You cannot switch, each interface type ***** a different hardware to be connected to it. The module features two serial interfaces, so besides ASC0 there is also ASC1. It is also possible to use the software multiplexer on a serial interface.
Thanks for your answer.
So, if I understood properly, if I use SPI which has four GPIO lines GPIO3 --> SPI_CLK (shared with ASC0), GPIO16 --> MOSI, GPIO17 --> MISO and GPIO19 --> SPI_CS (shared with ASC1), I can't use ASC0 anymore, isn't it? even if I onla need TX/RX.
If you configure shared ASC0 lines for other interfaces you of cours can't use these lines for ASC0 but you can still use ASC0 interface without these lines as RX/TX lines are not shared. You can also use hardware flow control with RTS/CTS lines which are not shared.
In case of ASC1 RX/TX and CTS are shared with SPI so you can't use SPI and ASC1.
Here's the table from hardware interface description document for ELS61-E R2:
OK, I understood now.