ds90ub949 无法读取edid

Chao Qin

Intellectual 260 points

DS90UB949 和 DS90UB940 配合使用。

HDP 可以拉高，但是用示波器抓不到DS90UB949 DDC_SCL 和 DDC_SDA 的波形。

设置从DS90UB949内部EDID SRAM里读取EDID。EDID用的是默认的，没有改动过。

HDMI源用的是Dongle 同屏器，可以确认源是好的。

5 年多前

0 Mickey Zhang 5 年多前

TI__Genius 14746 points

请确认下949与940是否正确link好。

0 Chao Qin 5 年多前回复 Mickey Zhang

Intellectual 260 points

Hi 张工：
谢谢回复。

连上HDMI Dongle，连着FPD-link，我把ds90ub949的寄存器dump出来了。
寄存器0x0c的值为0x03.

DES Error CRC error(s) during normal communication with Deserializer. This bit is cleared upon
loss of link or assertion of 0x04[5].
0: No CRC errors detected.
1: CRC error(s) detected.
If PORT1_SEL is set, this register is with reference to Port1.

Link Detect Link detect status:
0: Cable link not detected.
1: Cable link detected.
If PORT1_SEL is set, this register is with reference to Port1

可以检测到cable link 但是有CRC错误。

我再检查一下940那部分，看有什么问题，谢谢。

以下是完整的949寄存器的值。
root@salvator-x:~# i2cdump -f -y 4 0x0c
No size specified (using byte-data access)
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: 18 00 00 d2 80 00 60 00 00 00 02 00 03 20 00 00
10: 00 00 00 88 00 01 fe 1e 7f 7f 01 00 00 00 01 00
20: 0b 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
40: 14 55 00 00 80 00 00 00 00 00 00 00 00 00 00 00
50: 97 a1 1e 00 28 0c 00 00 00 00 92 20 02 06 44 00
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 a8 00 68 38 00 00 c0 00 00 00 00 00 ff 00
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
e0: 00 00 a8 00 68 38 00 00 00 00 00 00 00 00 00 00
f0: 5f 55 42 39 34 39 00 00 00 00 00 00 00 00 00 00