I use optimal charge mode, enshure that the EOC pin (with pull-up resistor) is LOW, set bit 2 in register at address 0x10 to enable Flash, but LED Flashing does not occur. When I repeat this cycle (enable Flash, wait 200ms (Flashing time was set to 192ms), then Start optimal charging, EOC pin goes low at once, (because supercapacitor already charged)), wait 1s, after 10-15 such cycles Flash occur as it should be. Communication with LM3550 is correct, because each sent byte is acknowledged.
Register configuration is as follows:
Address Value
0xB0 0x0B
0xA0 0x00
0x10 0x04 when in Flash mode
0x10 0x02 when in Optimal Charge mode
0xC0 Power on value
0xD0 Power on value