Datasheet

3.3.4 Having a chat with a green-dot Davis data logger

Using a BusPirate [18] in SPI mode, the AT45DB011 status byte and the security register

can be read from an original Davis data logger. This step is by no means required, but

it can be a useful tool to extract the contents of the securty register in the AT45DB011

DataFlash chip.

The BusPirate is connected to a PC via a USB cable. Use a terminal emulator such

as HyperTerminal (once included in Microsoft Windows distributions) or RealTerm [9] to

communicate with the BusPirate. Serial line communication parameters are 115200-8-

N-1.

The pins referred to below are numbered as shown in ﬁgure 5. Please take note of

the ”orientation” note just below the ﬁgure.

BusPirate Original Davis data logger

Pin name Pin name Pin #

CS SS 1

CLK SCK 2

MOSI MOSI 3

MISO MISO 4

3V3 – VPU VCC 13/14

GND GND 15/16

Table 2: Wire routing between the BusPirate header and the original Davis data logger. Also make

a connection from 3V3 to the VPU pin, both on the BusPirate header (BusPirate version 4 users can

probably use the ”e” command instead — refer to the BusPirate documentation [18] for details). Always

keep the SPI wires as short as possible.

The BusPirate needs to be conﬁgured with the correct SPI parameters. Note that

the BusPirate command interpreter is case-sensitive. These conﬁguration settings have

proven to work well, although some of them don’t really make any sense (commands

listed at left, comments at right):

m Set mode (entering interactive menu)

5 SPI

1 Speed: 30 kHz

1 Clock polarity: idle when low

2 Output clock edge: active to idle

1 Input sample phase: middle

2 CS: /CS

2 Output type: normal (H=3.3V, L=GND)

W On-board power supply ON

P On-board pullup resistors ON

http://meteo.annoyingdesigns.com 13