README
1CONTENT:
2
3 epic.h
4 epic1.c
5 epic2.s
6
7WHAT ARE THESE FILES:
8
9These files contain MPC8240 (Kahlua) EPIC
10driver routines. The driver routines are not
11written for any specific operating system.
12They serves the purpose of code sample, and
13jump-start for using the MPC8240 EPIC unit.
14
15For the reason of correctness of C language
16syntax, these files are compiled by Metaware
17C compiler and assembler.
18
19ENDIAN NOTATION:
20
21The algorithm is designed for big-endian mode,
22software is responsible for byte swapping.
23
24USAGE:
25
261. The host system that is running on MPC8240
27 shall link the files listed here. The memory
28 location of driver routines shall take into
29 account of that driver routines need to run
30 in supervisor mode and they process external
31 interrupts.
32
33 The routine epic_exception shall be called by
34 exception vector at location 0x500, i.e.,
35 603e core external exception vector.
36
372. The host system is responsible for configuring
38 the MPC8240 including Embedded Utilities Memory
39 Block. All EPIC driver functions require the
40 content of Embedded Utilities Memory Block
41 Base Address Register, EUMBBAR, as the first
42 parameter.
43
443. Before EPIC unit of MPC8240 can be used,
45 initialize EPIC unit by calling epicInit
46 with the corresponding parameters.
47
48 The initialization shall disable the 603e
49 core External Exception by calling CoreExtIntDisable( ).
50 Next, call epicInit( ). Last, enable the 603e core
51 External Exception by calling CoreExtIntEnable( ).
52
534. After EPIC unit has been successfully initialized,
54 epicIntSourceSet( ) shall be used to register each
55 external interrupt source. Anytime, an external
56 interrupt source can be disabled or enabled by
57 calling corresponding function, epicIntDisable( ),
58 or epicIntEnable( ).
59
60 Global Timers' resource, base count and frequency,
61 can be changed by calling epicTmFrequencySet( )
62 and epicTmBaseSet( ).
63
64 To stop counting a specific global timer, use
65 the function, epicTmInhibit while epicTmEnable
66 can be used to start counting a timer.
67
685. To mask a set of external interrupts that are
69 are certain level below, epicIntPrioritySet( )
70 can be used. For example, if the processor's
71 current task priority register is set to 0x7,
72 only interrupts of priority 0x8 or higher will
73 be passed to the processor.
74
75 Be careful when using this function. It may
76 corrupt the current interrupt pending, selector,
77 and request registers, resulting an invalid vetor.
78
79 After enabling an interrupt, disable it may also
80 cause an invalid vector. User may consider using
81 the spurious vector interrupt service routine to
82 handle this case.
83
846. The EPIC driver routines contains a set
85 of utilities, Set and Get, for host system
86 to query and modify the desired EPIC source
87 registers.
88
897. Each external interrupt source shall register
90 its interrupt service routine. The routine
91 shall contain all interrupt source specific
92 processes and keep as short as possible.
93
94 Special customized end of interrupt routine
95 is optional. If it is needed, it shall contain
96 the external interrupt source specific end of
97 interrupt process.
98
99 External interrupt exception vector at 0x500
100 shall always call the epicEOI just before
101 rfi instruction. Refer to the routine,
102 epic_exception, for a code sample.
103