FTDI_MODE1
FTDI_MODE0
BOOT_MODE0
Configuration
(BCBUS6)
(BCBUS5)
(BCBUS4)
0
0
1
Slave serial configuration via FTDI
0
1
X
FTDI device pins connected to module I2C bus
1
0
0
SPI flash programming via FTDI
X
1
0
Master serial configuration (Mercury module is
configured from SPI flash)
1
1
X
FTDI device pins connected to Mercury module
UART pins
Table 26: FTDI Configuration Settings - Port B
The control signals FTDI_MODE0 and FTDI_MODE1 are used to configure the way BDBUS0-3 pins are routed
on the module: to UART, I2C, SPI flash or Mercury module SPI configuration port.
Please note that for the SPI flash programming SRST#_RDY# (BCBUS2) must be pulled low. For the slave/-
passive serial configuration BOOT_MODE0 must be pulled high or left open, while for master/active serial
configuration BOOT_MODE0 must be pulled low.
Warning!
After Mercury module slave/passive serial configuration or SPI flash programming operations, the
FTDI_MODE0 signal must be pulled high, to avoid damaging the equipped Mercury module device.
6.6
I2C Communication
There are several I2C devices on the ST1 base board connected to two separate I2C buses. The
Mercury module and the FTDI device can be I2C masters on the main I2C bus. An overview of the I2C
structure is given in Table 27 and Figure 13. The I2C devices located on the Mercury module are shown in a
dashed box in Figure 13.
Please note that all I2C addresses are written in a 7-bit hexadecimal format.
D-0000-456-001
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Version 02, 23.07.2020
