1 ;======================================================================
4 ; This file implements panic_routine, which is called by the
5 ; `panic' macro in panic.inc. See panic.inc for the functionality
10 ;---------------------------------------------------------------------------
11 ; reserved access bank locations
15 ; used in panic routine for temporary storage:
19 register_counter res 1
22 panic_address res 1 ; condensed form of message start addr.
23 panic_morse res 1 ; # bytes of morse msg in panic readout
24 panic_regs res 1 ; # registers in panic readout
27 ;****************************************************************************
31 ;****************************************************************************
34 ; switch off interrupts and power
35 ; reconfigure timer0 for writing diagnostic msg to the LED
37 clr_f INTCON ; disable all interrupts EVER
38 bc_f PORTC,1 ; switch off booster
40 ; now we have time to copy the panic message address out of WREG
41 ; (turning off interrupts is urgent (we might get interrupted while
42 ; panicing which would be bad because we might forget to panic).
45 clr_f STKPTR ; avoids stack overruns
47 ; re-initialise timer0 config
48 mov_lw (1<<TMR0ON) | morse_t0scale ; Enable, 16-bit, timer, prescaler
51 ; get # bytes of morse msg, # registers in panic readout, message start addr.
52 ; back from condensed message start addr. stored in panic_address
55 mov_lw 4 ; size of each message's details
59 add_lw (morse_messages_start)/256
63 tblrd *+ ; read 1st byte of error message
64 ; (gives # bytes morse, # bytes registers)
65 dw 0xffff ; silicon errata: B4 issue 4
67 mov_ff TABLAT,panic_morse
69 and_wff panic_morse ; panic_morse now contains # bytes of morse msgs
71 mov_ff TABLAT,panic_regs
74 swap_f panic_regs ; panic_regs now contains # registers to read
78 rcall morsemsg ; transmit morse in red
82 rcall registermsg ; transmit contents of registers in
83 ; red(=low) and blue(=high)
87 ;****************************************************************************
91 ; wrapper round morse_readout to flash the per-pic led red for a morse msg
94 clr_f morse_counter ; clear loop counter
98 cmp_fw_ifge morse_counter ; if loop counter >=panic_morse
99 return ; return to panic
102 mov_ff TABLAT,flash_pattern
108 ;--------------------------
111 ; Flashes the per-pic led and black in a specified pattern.
113 ; The pattern is specified as the state for 8 identically-long time
114 ; periods each as long as a morse `dot', encoded into a byte with
115 ; most significant bit first.
118 ; flash_pattern flash pattern preserved
119 ; bit_counter any undefined
126 dec_f_ifz bit_counter ; done all the bits yet ?
130 rl_f flash_pattern ; top bit goes into N,
132 bra_n morse_readout_if_led_1
134 morse_readout_if_led_0
136 bra morse_readout_endif_led
138 morse_readout_if_led_1
141 morse_readout_endif_led
143 bra morse_readout_loop
145 ;--------------------------
146 ;--------------------------
150 clr_f register_counter ; clear loop counter
154 cmp_fw_ifge register_counter ; if loop counter >=panic_regs
155 return ; return to panic
159 mov_fw TABLAT ; TABLAT has the 8-bit version
160 mov_wf FSR0L ; of the address. So, 8 bits
161 ; go straight into FSR0L.
163 mov_lw 0x0f ; For FSR0H, we see if the
164 mov_fw FSR0H ; address XX is >=0x60.
165 ; If it is then we meant 0xfXX;
166 mov_lw 0x5f ; if not then we meant 0x0XX.
167 cmp_fw_ifle FSR0L ; (This is just like PIC does
168 clr_f FSR0H ; for insns using Access Bank)
170 mov_ff INDF0,flash_pattern
171 rcall register_readout
173 inc_f register_counter ;increment loop counter
178 ;--------------------------
182 ; Flashes the per-pic led red(0) and green(1) in a specified pattern.
183 ; (black gap between each bit)
185 ; The pattern is specified as the state for 8 identically-long time
186 ; periods each as long as a morse `dot', encoded into a byte with
187 ; most significant bit first.
190 ; flash_pattern flash pattern preserved
191 ; bit_counter any undefined
193 clr_f bit_counter ; clear loop counter
197 register_readout_loop
199 cmp_fw_ifge bit_counter ; if loop counter >=8 (register
204 cmp_fw_ifne bit_counter ; if loop counter !=4 (nybble length),
205 ; skip insertion of extra black space
206 bra not_nybble_boundary
210 rl_f flash_pattern ; top bit goes into N flag,
212 bra_n register_readout_if_led_1
214 register_readout_if_led_0
216 bra register_readout_endif_led
218 register_readout_if_led_1
221 register_readout_endif_led
222 inc_f bit_counter ; increment loop counter
226 bra register_readout_loop
229 ;****************************************************************************
230 ; GENERAL SUBROUTINES
232 ;----------------------------------------
233 waiting16 rcall waiting8
234 waiting8 rcall waiting4
235 waiting4 rcall waiting2
236 waiting2 rcall waiting
238 ; waits for a fixed interval, depending on the configuration of TMR0
240 bc_f INTCON,2 ; clear timer0 interrupt bit (p109)
241 ; Interrupt happens on overflow. So start at 65535-morse_t0cycles:
242 mov_lw (65535-morse_t0cycles) / 256
243 mov_wf TMR0H ; p107 set high byte of timer0 (buffered,
244 ; only actually set when write to tmr0l occurs)
245 mov_lw (65535-morse_t0cycles) & 0xff
246 mov_wf TMR0L ; set timer0 low byte - timer now set
248 bt_f_if0 INTCON,TMR0IF
249 bra waiting_loop ; wait for timer0 interrupt
253 ;****************************************************************************