UART

J4 has a pin that is connected to U2's UART.

Startup log

On startup, on RX pin following data is printed:

郣d 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Rd 38ee
Mem Addr (0x3a6) 0
Mem Addr (0x340) 2a45
Mem Addr (0x342) 2b89
Mem Addr (0x344) 1121
Mem Addr (0x346) 1
Mem Addr (0x348) a2
Mem Addr (0x34a) 38ee
Mem Addr (0x34e) 0
Mem Addr (0xb4) 22f8
Timer Init
version: 7.1.2.0.11.20161116 星期三
iic clock 200000 !
HDMITX I2C Read error, reg = 02
regDeviceID:0x7
---Disable HDMITx---
(382), threshold[0][0] = 0x4da, threshold[0][1] = 0x5b3
(382), threshold[1][0] = 0x40b, threshold[1][1] = 0x4c0
(382), threshold[2][0] = 0x67, threshold[2][1] = 0x79
(382), threshold[3][0] = 0xce, threshold[3][1] = 0xf2
(382), threshold[4][0] = 0xb53, threshold[4][1] = 0x3ff
audio queue_id: 1
video queue_id: 2
MPS_COMMAND_SET_CAPTURE_DEVICE 3 mode 5
MPS_COMMAND_SET_ISP_MODE 0
channel name: AIR_CH_521_6M
--xcpu init--
cmd info addr: 0x2c1e848
ir data buf addr: 0x2c1f450
ir data write porinter: 0x2c1e658
[MainLoop] *irdataddr: 0x2c1f450, *irwptrddr: 0x2c1e658
[MainLoop] irwptr: 0x2c1e658, irbuf: 0x2c1f450
scg_0_*********
alloc addr: 0x2C209B8, buffer start: 0x2C209B8
tsbitrate: 23751336
after setting: 0x8001, tsoDivider: 1, oriClock: 800, tsBitRate: 80000000, tsoMBitRate: 80
tso out byte rate: 10000000 Bps, null count: 0
pcrClockSrc: 0, pcrDivider: 4
oriClock: 800, clockDivider: 5, pllClock: 160.000000
pcr clock: 40.000000
Enable Hw pcr
tso.c(199), PCR clock : 40.000000 Mhz, regVal: 0xA0
set gpio 13
start write buffer: 0x2C209B8
injectBound: 1063, tso: 10000000, period: 20, injectTime: 1800
90K value per 188 packet: 1, tick in micro: 200
pcr Pid: 0x7D1
service 0: video: 0x7D1, audio: 0x7D2
PCR Pid: 0x7D1 is video pid
9919 Block = 1, (0)
change device ID(3)
AspectRatio src = 0, 0, 0, 0, dst = 0, 0, 1280, 720
Index 8 W 1280 H 720 B 12000 De 0 0 S 0 GOP 120 AS 0
AV_SYNC_TIMER_INIT -- baseTime = 0
dur(17) frame rate(6) = (0)
Frame rate 6
Encode w 1280 h 720 b 12000 deinter 0 0 fps 6
AV_SYNC_DO_SYNC_INIT Vid 66  Aud 50 FR 0 FP 0 initDiff 0
First Out Video Timestamp: 316
threshold byte rate: 1228800, per frame size: 20480 bytes

Available also as file here.