| wdenk | 327f7a0 | 2001-11-28 17:49:55 +0000 | [diff] [blame] | 1 | CONTENT: |
| 2 | |
| 3 | epic.h |
| 4 | epic1.c |
| 5 | epic2.s |
| 6 | |
| 7 | WHAT ARE THESE FILES: |
| 8 | |
| 9 | These files contain MPC8240 (Kahlua) EPIC |
| 10 | driver routines. The driver routines are not |
| 11 | written for any specific operating system. |
| 12 | They serves the purpose of code sample, and |
| 13 | jump-start for using the MPC8240 EPIC unit. |
| 14 | |
| 15 | For the reason of correctness of C language |
| 16 | syntax, these files are compiled by Metaware |
| 17 | C compiler and assembler. |
| 18 | |
| 19 | ENDIAN NOTATION: |
| 20 | |
| 21 | The algorithm is designed for big-endian mode, |
| 22 | software is responsible for byte swapping. |
| 23 | |
| 24 | USAGE: |
| 25 | |
| 26 | 1. 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 | |
| 37 | 2. 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 | |
| 44 | 3. 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 | |
| 53 | 4. 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 | |
| 68 | 5. 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 | |
| 84 | 6. 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 | |
| 89 | 7. 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. |