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+--- Thread: 4 Uarts and 2 Ethernet possiblities (/showthread.php?tid=7349)
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4 Uarts and 2 Ethernet possiblities - gops - 04-04-2019
We have below requirements and questions, please help with pointers for our research.
1. We need 4 UARTs
2. 2 ethernet(s) [100 Mbps is fine], one natively available, what is the best option to add second one?
3. WIFI/BLE
Though we look for Industrial Temperature, considering RockPro64 LTS' 0-70 temp is good for factories that we aim for.
How many hardware UARTs RockPro64 supports, somehow we could not find the straight answers.
Is it possible to enable some GPIO pins to be UART? We want to connect 4 RS 485 channels on 4 UARTS, can RockPro64 could supply power for same along with 2 Ethernets while in use?
RE: 4 Uarts and 2 Ethernet possiblities - martinayotte - 04-04-2019
(04-04-2019, 12:20 PM)gops Wrote: 1. We need 4 UARTs
Is it possible to enable some GPIO pins to be UART? We want to connect 4 RS 485 channels on 4 UARTS
On the GPIO header, there is only the UART2DBG.
What I suggest you is to build a piggy back board with 2 SC16IS752, which is a Dual Uart chip attached on SPI bus, that way, you will get 4 GPIO with HalfDuplex capability for RS485.
RE: 4 Uarts and 2 Ethernet possiblities - gops - 04-04-2019
Thank you, Is one UART design followed due to Raspberry PI compatible pins?
As many RPI2 styled interfaces provides 1 or 2 UARTs.
RE: 4 Uarts and 2 Ethernet possiblities - martinayotte - 04-05-2019
(04-04-2019, 08:17 PM)gops Wrote: Thank you, Is one UART design followed due to Raspberry PI compatible pins?
As many RPI2 styled interfaces provides 1 or 2 UARTs.
Non necessarily ... There is a second UART, the UART4 available on pins 19/21, but it is shared with SPI pins.
It is better to use those SPI pins for attaching the SC16IS752 chips ...
RE: 4 Uarts and 2 Ethernet possiblities - LMM - 04-05-2019
(04-04-2019, 12:20 PM)gops Wrote: 2. 2 ethernet(s) [100 Mbps is fine], one natively available, what is the best option to add second one?
Concerning a second NIC, I use a USB 3 Gigabit Ethernet adapter, it works quite well. To configure it, one needs to add a yaml file in /etc/netplan (in ubuntu)
LMM.
RE: 4 Uarts and 2 Ethernet possiblities - gops - 04-05-2019
(04-05-2019, 09:58 AM)LMM Wrote:(04-04-2019, 12:20 PM)gops Wrote: 2. 2 ethernet(s) [100 Mbps is fine], one natively available, what is the best option to add second one?
Concerning a second NIC, I use a USB 3 Gigabit Ethernet adapter, it works quite well. To configure it, one needs to add a yaml file in /etc/netplan (in ubuntu)
LMM.
Thanks for great suggestion martinayotte and LMM.
Any recommendation as module for USB to Ethernet, instead of we connect USB to Ethernet from outside connector, I mean, we would like make a daughter board with a small PCB with host 4 RS 485 (with SC16IS752 x 2), 1 Ethernet USB port. Any concerns like how RockPro64 help with power supply all ports.
RE: 4 Uarts and 2 Ethernet possiblities - pistoletov - 06-27-2019
i need a 1 rs485 uart on Rock64 board. does it possible to use UART2 with max485 level converter? Or i have to use
SC16IS752 chip. Does it suported in kernel? My java application use /dev/tty style 485 usart for modbus communication.
May be exist better solution for my problem.
RE: 4 Uarts and 2 Ethernet possiblities - martinayotte - 06-27-2019
Beware that you also need to control RTS for RS485 flow direction ...
If you don't want to bother with driver or this flow direction, you are better luck using a USB-RS485 dongle such as this one :
https://www.ebay.ca/itm/2PCS-CH340-USB-to-RS485-485-Converter-Adapter-Module-For-Win7-Linux-XP-Vista/151911412433
RE: 4 Uarts and 2 Ethernet possiblities - pistoletov - 06-27-2019
(06-27-2019, 09:29 AM)martinayotte Wrote: Beware that you also need to control RTS for RS485 flow direction ...
If you don't want to bother with driver or this flow direction, you are better luck using a USB-RS485 dongle such as this one :
https://www.ebay.ca/itm/2PCS-CH340-USB-to-RS485-485-Converter-Adapter-Module-For-Win7-Linux-XP-Vista/151911412433
thank you for reply. I know about this pin for direction. In other forum (armbian) i saw yours post about using RTS signal for this. I have a allwiner board to but i can't find kernel module which support uart rts signal. I know about usb-485 adapters whis is cheap but i do not have free usb ports..
RE: 4 Uarts and 2 Ethernet possiblities - richardk - 06-27-2019
(06-27-2019, 11:23 AM)pistoletov Wrote:RS485 might be difficult to control via software, if the speeds are high.(06-27-2019, 09:29 AM)martinayotte Wrote: Beware that you also need to control RTS for RS485 flow direction ...
If you don't want to bother with driver or this flow direction, you are better luck using a USB-RS485 dongle such as this one :
https://www.ebay.ca/itm/2PCS-CH340-USB-to-RS485-485-Converter-Adapter-Module-For-Win7-Linux-XP-Vista/151911412433
thank you for reply. I know about this pin for direction. In other forum (armbian) i saw yours post about using RTS signal for this. I have a allwiner board to but i can't find kernel module which support uart rts signal. I know about usb-485 adapters whis is cheap but i do not have free usb ports..
Actually, you might consider a Beaglebone Black or Green. It has 5 UARTs available, and it can support RS485 with buffers (like the MAX485). You can plug in a second Ethernet via USB.