I'm using ESP-WROOM-02 on a custom board.
I wrote a simple blink probram using ESP8266_NONOS_SDK_V1.5.2_16_01_29, and it *sometimes works* and *sometimes not*.
The main.c is here: https://gist.github.com/mash/0f5b1a2d85 ... fdd8706c2d
When I observe the UART1 debug line,
when it successfully starts, it outputs this:
Code: Select all
ets Jan 8 2013,rst cause:1, boot mode:(3,7)
load 0x40100000, len 1856, room 16
tail 0
chksum 0x63
load 0x3ffe8000, len 776, room 8
tail 0
chksum 0x02
load 0x3ffe8310, len 552, room 8
tail 0
chksum 0x79
csum 0x79
2nd boot version : 1.5
SPI Speed : 40MHz
SPI Mode : QIO
SPI Flash Size & Map: 32Mbit(1024KB+1024KB)
jump to run user1 @ 1000
when it doesn't work, UART1 doesn't output anything.
When it enters this state,
it outputs HIGH on IO4 and IO16 (these are connected to LEDs).
It doesn't recover even if I pull down RST to low and back to high again.
IO15 is directly connected to GND,
IO2 pulled up with 10k resistor,
IO0 pulled up with 10k resistor.
The probability that this problem happens is around 50%.
If I add a 100uF capacitor between EN and GND, the probability goes down to around 10%, but it still happens.
What's happening?
How can I fix this problem?
Thanks in advance.