Other Parts Discussed in Thread: AM3358
Hello,
In our design, we use mmc3(mmc@47810000) of am3358 to connect to our wifi-sdio module.
Since the pin level of am335x is configured to 3.3V, we used a level conversion chip (LSF0108PWR) to convert the level to 1.8V used by the wifi module.
After power-on, although the WiFi module can work normally, but the WiFi max speed is only 37Mbits/s, which is lower than our expectation(>100Mbits/s).
[root@st-am335x ~] # iperf3 -c 192.168.50.20 -u -b 200M -t 10 Connecting to host 192.168.50.20, port 5201 [ 5] local 192.168.50.3 port 57609 connected to 192.168.50.20 port 5201 [ ID] Interval Transfer Bitrate Total Datagrams [ 5] 0.00-1.00 sec 4.25 MBytes 35.6 Mbits/sec 3052 [ 5] 1.00-2.00 sec 4.46 MBytes 37.4 Mbits/sec 3200 [ 5] 2.00-3.00 sec 4.46 MBytes 37.4 Mbits/sec 3201 [ 5] 3.00-4.00 sec 4.46 MBytes 37.4 Mbits/sec 3200 [ 5] 4.00-5.00 sec 4.45 MBytes 37.4 Mbits/sec 3198 [ 5] 5.00-6.00 sec 4.45 MBytes 37.4 Mbits/sec 3199 [ 5] 6.00-7.00 sec 4.46 MBytes 37.4 Mbits/sec 3200 [ 5] 7.00-8.00 sec 4.46 MBytes 37.4 Mbits/sec 3201 [ 5] 8.00-9.00 sec 4.45 MBytes 37.4 Mbits/sec 3199 [ 5] 9.00-10.00 sec 4.46 MBytes 37.4 Mbits/sec 3200 - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams [ 5] 0.00-10.00 sec 44.3 MBytes 37.2 Mbits/sec 0.000 ms 0/31850 (0%) sender [ 5] 0.00-10.00 sec 44.3 MBytes 37.2 Mbits/sec 0.326 ms 0/31839 (0%) receiver
Using cat got the following information
[root@st-am335x ~] # cat /debugfs/mmc1/clock 50000000 [root@st-am335x ~] # cat /debugfs/mmc1/ios clock: 50000000 Hz vdd: 21 (3.3 ~ 3.4 V) bus mode: 2 (push-pull) chip select: 0 (don't care) power mode: 2 (on) bus width: 2 (4 bits) timing spec: 2 (sd high-speed) signal voltage: 0 (3.30 V) driver type: 0 (driver type B)
Is it because the use of LSF0108PWR and our mmc level does not meet the requirements of 1.8V？ If it is, can configuring the data level of mmc to open-drain and pull up with an external power of 1.8V solve the problem?
Thanks.
