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perf: Optimize telemetry packet generation and reduce commutation int…
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…erference
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@mathiasvr
mathiasvr committed Dec 14, 2020
1 parent 97d9cdc commit b3b8560
Showing 1 changed file with 66 additions and 75 deletions.
141 changes: 66 additions & 75 deletions Bluejay.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -172,6 +172,7 @@ Flag_RCP_STOP BIT Flags3.5 ; Set if the RC pulse value is zero

Tlm_Data_L: DS 1 ; DShot telemetry data low byte
Tlm_Data_H: DS 1 ; DShot telemetry data high byte
Tmp_B: DS 1

DSEG AT 30h ; Ram data segment, direct addressing
Power_On_Wait_Cnt_L: DS 1 ; Power on wait counter (lo byte)
Expand Down Expand Up @@ -387,10 +388,34 @@ ENDM

DShot_GCR_Get_Time MACRO
mov A, DShot_GCR_Pulse_Time_2
cjne A, B, ($+5)
cjne A, Tmp_B, ($+5)
mov A, DShot_GCR_Pulse_Time_3
ENDM

; Prepare telemetry packet while waiting for timer 3 to wrap
Wait_For_Timer3 MACRO
LOCAL wait_for_t3 done_waiting
jb Flag_PACKET_PENDING, wait_for_t3
jb Flag_TLM_ACTIVE, wait_for_t3

jnb Flag_T3_PENDING, done_waiting
call dshot_packet_factory

wait_for_t3:
jnb Flag_T3_PENDING, done_waiting
sjmp wait_for_t3

done_waiting:
ENDM

Early_Return_Packet_Stage MACRO num
inc Temp5
jb Flag_T3_PENDING, dshot_packet_stage_&num ;; return early if timer 3 has wrapped
pop PSW
ret
dshot_packet_stage_&num:
ENDM

IF FETON_DELAY == 0
PWM_CENTERED EQU 0
ELSE
Expand Down Expand Up @@ -1132,91 +1157,91 @@ dshot_gcr_encode_jump_table:
; GCR encoding is ordered by least significant bit first,
; and represented as pulse durations.
dshot_gcr_encode_0_11001:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_3
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_1_11011:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_2_10010:
DShot_GCR_Get_Time
Push_Mem Temp1, A
Push_Mem Temp1, DShot_GCR_Pulse_Time_3
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_3_10011:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_3
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_4_11101:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_5_10101:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_6_10110:
DShot_GCR_Get_Time
Push_Mem Temp1, A
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_7_10111:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_8_11010:
DShot_GCR_Get_Time
Push_Mem Temp1, A
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_9_01001:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_3
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret

dshot_gcr_encode_A_01010:
DShot_GCR_Get_Time
Push_Mem Temp1, A
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret

dshot_gcr_encode_B_01011:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret

dshot_gcr_encode_C_11110:
Expand All @@ -1225,30 +1250,30 @@ dshot_gcr_encode_C_11110:
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_1
mov Tmp_B, DShot_GCR_Pulse_Time_1
ret

dshot_gcr_encode_D_01101:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_2
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret

dshot_gcr_encode_E_01110:
DShot_GCR_Get_Time
Push_Mem Temp1, A
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret

dshot_gcr_encode_F_01111:
Push_Mem Temp1, B
Push_Mem Temp1, Tmp_B
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
Push_Mem Temp1, DShot_GCR_Pulse_Time_1
mov B, DShot_GCR_Pulse_Time_2
mov Tmp_B, DShot_GCR_Pulse_Time_2
ret


Expand Down Expand Up @@ -1381,10 +1406,7 @@ dshot_packet_stage_1:
addc A, Temp2
mov Tlm_Data_H, A

inc Temp5
pop PSW
ret
dshot_packet_stage_2:
Early_Return_Packet_Stage 2
mov A, Tlm_Data_H

; 12-bit encode telemetry data
Expand All @@ -1394,14 +1416,10 @@ dshot_packet_stage_2:

; If period is zero then reset to FFFFh (FFFh for 12-bit)
mov Tlm_Data_H, #0Fh
mov A, #0FFh
mov Tlm_Data_L, A
mov Tlm_Data_L, #0FFh

dshot_tlm_12bit_encoded:
inc Temp5
pop PSW
ret
dshot_packet_stage_3:
Early_Return_Packet_Stage 3
mov A, Tlm_Data_L

; Compute inverted xor checksum (4-bit)
Expand All @@ -1412,42 +1430,27 @@ dshot_packet_stage_3:

; GCR encode the telemetry data (16-bit)
mov Temp1, #Temp_Storage ; Store pulse timings in Temp_Storage
mov B, DShot_GCR_Pulse_Time_1 ; Final transition time
mov Tmp_B, DShot_GCR_Pulse_Time_1 ; Final transition time

call dshot_gcr_encode ; GCR encode lowest 4-bit of A (store through Temp1)

mov Temp6, B
inc Temp5
pop PSW
ret
dshot_packet_stage_4:
mov B, Temp6
Early_Return_Packet_Stage 4

mov A, Tlm_Data_L
call dshot_gcr_encode

mov Temp6, B
inc Temp5
pop PSW
ret
dshot_packet_stage_5:
mov B, Temp6
Early_Return_Packet_Stage 5

mov A, Tlm_Data_L
swap A
call dshot_gcr_encode

mov Temp6, B
inc Temp5
pop PSW
ret
dshot_packet_stage_6:
mov B, Temp6
Early_Return_Packet_Stage 6

mov A, Tlm_Data_H
call dshot_gcr_encode

Push_Mem Temp1, B ; Initial transition time
Push_Mem Temp1, Tmp_B ; Initial transition time

mov Temp5, #0
setb Flag_PACKET_PENDING
Expand Down Expand Up @@ -2067,20 +2070,7 @@ calc_new_wait_times_fast_done:
;
;**** **** **** **** **** **** **** **** **** **** **** **** ****
wait_advance_timing:

; DShot telemetry
jb Flag_PACKET_PENDING, wait_advance_timing_loop
jb Flag_TLM_ACTIVE, wait_advance_timing_loop

wait_advance_timing_loop2:
call dshot_packet_factory
jb Flag_PACKET_PENDING, wait_advance_timing_loop
jnb Flag_T3_PENDING, ($+5)
sjmp wait_advance_timing_loop2

wait_advance_timing_loop:
jnb Flag_T3_PENDING, ($+5)
sjmp wait_advance_timing_loop
Wait_For_Timer3

; Setup next wait time
mov TMR3RLL, Wt_ZC_Tout_Start_L
Expand Down Expand Up @@ -2255,8 +2245,7 @@ store_times_decrease_fast:
;
;**** **** **** **** **** **** **** **** **** **** **** **** ****
wait_before_zc_scan:
jnb Flag_T3_PENDING, ($+5)
sjmp wait_before_zc_scan
Wait_For_Timer3

mov Startup_Zc_Timeout_Cntd, #2
setup_zc_scan_timeout:
Expand Down Expand Up @@ -2570,8 +2559,7 @@ wait_for_comm:
Set_Pwms_Off

wait_for_comm_wait:
jnb Flag_T3_PENDING, ($+5)
sjmp wait_for_comm_wait
Wait_For_Timer3

; Setup next wait time
mov TMR3RLL, Wt_Zc_Scan_Start_L
Expand Down Expand Up @@ -3314,6 +3302,9 @@ beep_delay_set:
call wait100ms ; Wait for new RC pulse to be measured

wait_for_power_on_no_beep:
jb Flag_PACKET_PENDING, ($+6)
lcall dshot_packet_factory

call wait10ms
mov A, Rcp_Timeout_Cntd ; Load RC pulse timeout counter value
jnz wait_for_power_on_not_missing ; If it is not zero - proceed
Expand Down

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