# Setting Up the RS232 Interface

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Select a communication port, adjust the baudrate, and click Connect.

FLIP starts a synchronization sequence with the target device bootloader software. On completion of the sync sequence, FLIP reads the target device special bytes and updates the device parameters area.

If the synchronization sequence fails, you will get the following error message :

## Setting the baudrate

The baudrate must be choosen with care : if the target hardware oscillator frequency is too low, the bootloader cannot achieve characters reception/transmission and FLASH programming properly. FLIP will warn you through a message box if such a situation occurs.

In such cases, you have to decrease the baudrate.

The following tables show the valid oscillator frequencies versus baudrate which allow a secured RS232 transmission.

| 1.8432 | 2 | 2.4576 | 3.6864 | 4 | 5 | 6 | 7.3728 | 8
4800 | OK | OK | OK | OK | OK | OK | OK | OK | -
9600 | OK | OK | OK | OK | OK | - | OK | OK | OK
19200 | OK | OK | OK | OK | OK | OK | OK | OK | OK
38400 | - | OK | - | OK | OK | OK | OK | OK | OK
57600 | - | - | - | OK | - | - | - | OK | -
115200 | - | - | - | - | - | - | - | OK | -

| 10 | 11.0592 | 12 | 14.318 | 14.746 | 16 | 20 | 24 | 32
4800 | OK | OK | OK | OK | OK | - | - | - | -
9600 | OK | OK | OK | OK | OK | OK | OK | OK | -
19200 | - | OK | OK | OK | OK | OK | OK | OK | OK
38400 | OK | OK | OK | OK | OK | - | - | OK | OK
57600 | - | OK | - | - | OK | OK | OK | OK | OK
115200 | - | OK | - | - | OK | - | - | - | OK

Note that these tables show guaranteed frequency / baudrate pairs. On recent versions of bootloaders, the autobaud calculation algorithm has been improved, reducing the number of non compatible frequency / baudrate pairs. Please consult the bootloader specification or the device data-sheet for up-to-date information.

## Setting Manual Synchronization

It may happen, particularly on Laptop machines, that the UART Tx signal toggle when opening the port, launching the bootloader's baudrate calculation routine before FLIP sends the synchronization character. This unexpected behaviour produces erroneous baudrate calculation results.

FLIP offers the capability of controlling the order of operations during the synchronization steps.

### Sequence of Operations

In order to manually control the synchronization process, perform the following steps :

1. Check the Manual Sync checkbox.

2. Click Connect (FLIP opens the RS232 port but does not send the sync character).

3. Verify that the hardware conditions are properly set on the target system.

4. Reset the target system.

5. Click Sync (FLIP sends the sync character).

### Manual Synchronization and AutoISP

Manual Sync and AutoIsp are incompatible operating modes. If AutoIsp has been activated, the Manual Sync checkbox is disabled.