Some of them are quite small so a magnifier is also handy. In addition to board test program, you will need a multimeter with thin sharp test leads to measure voltage and resistance between board elements. Therefore, when I see short SPI and GPIO tests passed and long SPI test fail I know that it’s actually a crystal which is dead, not SPI. The reason for this is that due to MAX3421E internal organization both short SPI test (reading REVISION register) and GPIO read/write doesn’t require working crystal oscillator, whereas long SPI test (reading/writing any other register) will fail and stop if crystal is defective. Also, GPIO test is placed between short and long SPI tests. This test is made optional – if you don’t connect GPIO lines as described, the test will print an error message and continue with the next test. GPIO lines are checked using a loopback adapter – a thing that connects GPIN0 to GPOUT0, GPIN1 to GPOUT1, and so on. The main loop is written so that any test can be turned off if necessary by commenting out a single line.
The sketch tests 4 major parts of the circuit – SPI interface, general purpose input/output pins (GPIO), quartz crystal oscillator, and finally USB SIE. Two files are necessary – board_test.pde and board_test.h containing diagnostic messages. Much of the testing is performed using board test sketch, available from examples section on github.
XKEYS OSCULATOR MANUAL
This article presents next logical step – a service manual for Arduino USB Host Shield, sort of. With open source movement and general understanding that sharing information is beneficial, manufacturers resumed publishing schematic diagrams of their creations.
XKEYS OSCULATOR MANUALS
At some point, service manuals and schematics disappeared from the documentation for various reasons – equipment users were left to deal with manufacturer’s support or rely on their own reverse engineering skills. Complex devices, such as oscilloscopes, spectrum analyzers and other test instruments used to have service manuals containing detailed calibration and repair procedures. In the past, it was customary to include schematic with every electronic device documentation. I have been in correspondence with several electronics enthusiasts helping them getting their shields fixed and since their problems look similar to what I see when doing post-manufacturing quality control I decided to share my testing procedure along with some pictures. Consequently, occasional destroying of parts is natural and shall be anticipated. Making electronic devices requires close interaction with parts – reversing supply polarity, overloading inputs, and inadvertently shorting pins with test leads. The following test routine shall be used to test the board and generate test signals. Current revision (2.0.x) is slightly different and works under different software. This article covers revision 1 of the shield.
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