Figure 2-3: Main Clock Group Divide and Gating
To Flash
Controller
Clocks
cfg_h2f_user0_base_clk
Clock Gate
Clock Gate
Clock Gate
mpu_base_clk
main_base_clk
dbg_base_clk
mpu_clk
C0
C1
C2
C3
C4
C5
Main
PLL
main_qspi_base_clk
main_nand_sdmmc_base_clk
Clock Gate
l3_mp_clk
Clock Gate
l4_mp_clk
Clock Gate
Divide
by 2
Divide
by 4
Clock Gate
l4_sp_clk
Clock Gate
dbg_at_clk
Clock Gate
dbg_clk
Clock Gate
dbg_trace_clk
Clock Gate
dbg_timer_clk
Clock Gate
cfg_clk
Clock Gate
h2f_user0_clock
Divide by
1, 2, or 4
Divide
by 1 or 2
Divide by
1, 2, 4, 8, or 16
Divide
by 1 or 2
Divide
by 2 or 4
mpu_periph_clk
mpu_l2_ram_clk
l4_main_clk
periph_base_clk (from Peripheral PLL C4)
l3_main_clk
l3_sp_clk
Divide by
1, 2, 4, 8, or 16
Divide by
1, 2, 4, 8, or 16
The clocks derived from main PLL C0-C2 outputs are hardware-managed, meaning hardware ensures that
a clean transition occurs, and can have the following control values changed dynamically by software write
accesses to the control registers:
• PLL bypass
• PLL numerator, denominator, and counters
• External dividers
For these registers, hardware detects that the write has occurred and performs the correct sequence to ensure
that a glitch-free transition to the new clock value occurs. These clocks can pause during the transition.
Altera Corporation
Clock Manager
2-7
Main Clock Group
cv_54002
2013.12.30