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12 >Diagnostic Support</TITLE
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65 >Chapter 9. HAL Interfaces</TD
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85 NAME="HAL-DIAGNOSTIC-SUPPORT">Diagnostic Support</H1
87 >The HAL provides support for low level diagnostic IO. This is
88 particularly useful during early development as an aid to bringing up
89 a new platform. Usually this diagnostic channel is a UART or some
90 other serial IO device, but it may equally be a a memory
91 buffer, a simulator supported output channel, a ROM emulator virtual
92 UART, and LCD panel, a memory mapped video buffer or any other output
98 > performs any initialization
99 required on the device being used to generate diagnostic output. This
100 may include, for a UART, setting baud rate, and stop, parity and
101 character bits. For other devices it may include initializing a
102 controller or establishing contact with a remote device.</P
106 >HAL_DIAG_WRITE_CHAR(c)</TT
108 the character supplied to the diagnostic output device.</P
112 >HAL_DIAG_READ_CHAR(c)</TT
113 > reads a character from the
114 diagnostic device into the supplied variable. This is not supported
115 for all diagnostic devices.</P
117 >These macros are defined in the header file
120 >cyg/hal/hal_diag.h</TT
121 >. This file is usually supplied
122 by the variant or platform HAL, depending on where the IO device being
123 used is located. For example for on-chip UARTs it would be in the
124 variant HAL, but for a board-level LCD panel it would be in the
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